Argthtjtr

Why in most cases do not put the article "a", when you enter the sentence in the search?
In the example on this site, the article is adding (OALD (American English))

Just enter in the search and you will see that everywhere in different ways.

He is a racist

and

He is not a racist/I'm not a racist

Like so many other words in English (antique, chief, expert, orange, phony, suspect, etc.), "racist" works as both a noun and an adjective.

He is racist. (adjective)

He is a racist. (noun)

Both have approximately the same nuance, but are used differently. As an adjective "racist" can describe actions, concepts, and objects as well as people. Examples:

A racist decision.

A racist doctrine.

A racist document.

The noun "a racist" can only be applied to people, as in "a person who is racist".

Both are grammatically correct, and the difference is just about what nuance the author wants the sentence to have. They do have slightly different meanings, however. A racist is a person who is racist, which is the state of holding prejudice against a specific demographic. So the sentence "He is racist" is saying "He is prejudiced", whereas the sentence "He is a racist" is saying "He is the type of person who holds prejudices". Both mean approximately the same thing, just going at it from a different angle.

Depending on context, they can imply degrees of prejudice, but this is not intrinsic to the usage. In my experience, being called "a racist" is usually slightly more serious, just because "a racist" usually means they are a wholly racist and hateful person, whereas being called simply "racist" can mean the same thing, or a lesser degree, such as subconsciously fearing a minority even without hateful intention.

You mention entering the phrase into a search. Do you mean a search engine?

If that is the case, then the reason that people often omit articles from internet searches is that they're largely ignored by the search engine itself.

If you type...

He is a racist

...into a search engine, the search engine is going to ignore the 'a' because it appears possibly literally on every website on the internet. In other words searching for...

He is a racist

vs....

He is racist

...will very likely pull up the same search results.

If you add quotation marks, then the engine will search for that exact phrase:

"He is a racist"

...will return all websites where that exact sentence, including the 'a', appears, whereas...

"He is racist"

...will return all websites where that sentence appears.