Sorcerers are "spontaneous" spell casters. They don't "learn spells" the way a wizard does; their spells aren't granted by a powerful extraplanar entity the way a cleric's, paladin's, or warlock's are, they aren't drawn from nature like a druid's or ranger's. They have the same names, because they have the same effects -- but they come from innate magic within the sorcerer's being; a sorcerer becomes a sorcerer because of his magic. He can, with some experience, bend the spells, changing fundamentals of how they work (multiple targets, touch spells at a distance, and so forth), or rearrange spell slots.

Why, then, should sorcerers have to use material components to cast spells?

Bottom line -- is there reasoning given (beyond the small amount of material in the PHB) on why sorcerers have to use material components like "prepared spell" casters such as wizards, or divine casters like clerics? If you draw fire from your essence, why would you need a ball of bat guano?

Note that I am not looking for game design reasons (such as balance or anything about designer intent) to explain this, only in-universe explanations for why. Please support all answers with the appropriate evidence and support from lore and avoid conjecture.

Components are required by the spells to warp the Weave to create the effect

All spellcasters create magical effects by influencing the Weave:

Mortals can’t directly shape this raw magic. Instead, they make use of a fabric of magic, a kind of interface between the will of a spellcaster and the stuff of raw magic. [...] All magic depends on the Weave, though different kinds of magic access it in a variety of ways. The spells of wizards, warlocks, sorcerers, and bards are commonly called arcane magic. These spells rely on an understanding—learned or intuitive—of the workings of the Weave. The caster plucks directly at the strands of the Weave to create the desired effect.

It is never explicitly defined, but it seems that spells require components as some sort of requirement to "pluck" the strands of the weave and thus make the spell effect occur.

A spell's components are the physical requirements you must meet in order to cast it. Each spell's description indicates whether it requires verbal (V), somatic (S), or material (M) components. If you can't provide one or more of a spell's components, you are unable to cast the spell.

This restriction is inherent to magic at its base level and does not depend on class or source of magic:

Different character classes have distinctive ways of learning and preparing their spells, and monsters use spells in unique ways. Regardless of its source, a spell follows the rules here.

So while the precise lore reason is not explicitly defined, the answer is clear: sorcerers require components because they create effects by manipulating the weave in the same way as other arcane spellcasters and thus abide by the same broad magical rules as everyone else. There is nothing special about the way a sorcerer gets their power that would inherently make them different from any other caster in this respect.

Sorcerers are not innate casters

tl;dr Only innate casters don't require a focus or components. Sorcerers' spellcasting is not innate, even though their raw magic is. Spellcasting is learned and can be further developed.

...By learning to harness and channel their own inborn magic, they can discover new and staggering ways to unleash that power...

Innate casters are the ones who don't require focus nor components

For example, cloud giants have innate casting.

Innate Spellcasting. The giant's innate spellcasting ability is Charisma. It can innately cast the following spells, requiring no material components...

Contrasting with spellcasters that have learned to cast spells, innate casters always cast at the lowest level and can not change out their known spells.

Some spells require components (or a focus)

Spells are discrete effects regardless of how a character has learned to create them.

In casting a spell, a character carefully plucks at the invisible strands of raw magic suffusing the world, pins them in place in a particular pattern, sets them vibrating in a specific way, and then releases them to unleash the desired effect (Basic Rules, p. 82)

It is innate to the way that the world works that some of these discrete effects require materials (or an arcane focus) in order to "pluck at the invisible strands of raw magic suffusing the world".

It is used to focus their internal magic

I don't see why you would find it logical that casters that get their spells from an entity would need materiel components and sorcerers would not.

But to answer your question, sorcerers have the natural ability to pull from the Weave but they still need to focus this in some way. This can be done with a spellcasting focus if you really don't like material components as I'm sure you know.

As for the ruling, it doesn't really go much further than "Sorcerers are spellcasters" and "Spellcasters need material components.", as you can see in the PHB:

An event in your past, or in the life of a parent or ancestor, left an indelible mark on you, infusing you with arcane magic. This font of magic, whatever its origin, fuels your spells.

You can use an arcane focus (found in chapter 5) as a spellcasting focus for your sorcerer spells.

I do agree with your point and as with all the rules, if this bothers you I encourage you to homebrew it.

There is magic in all things and the magic of all things has a frequency unique to each thing. By focussing your magic in synergy with the magic of the material components a type of sympathetic reaction is created and this assists in producing the desired result similar to a recipe.

The most easily seen example of this is light focussed through a magnifying glass that produces the effect of heat. Yet another example is light focussed through a prism or even a drop of water to separate light into its constituent parts and form a rainbow. In much the same way you focus your magic through material components in the prescribed way to create the desired effect.

Some very strange fellows call this Physics but it is clearly magic!