Why it is important to avoid obscure words from your writing

I came across the following sentence in one of the essays that I recently corrected.

On a large scale, in the medias, where the subscriber base is humongous in general, there are a voluminous fabricated news, mainly because of favouritism and biases.

As you can see the student has used some uncommon words in the above sentence.

A lot of students are under the impression that they have to use obscure words to demonstrate their range of vocabulary. This is a mistake. When you use words that you do not normally use in speech or writing, you are more likely to make mistakes.

The above sentence, for example, has several mistakes in it. So how can we improve it? Here are a few suggestions.

In mainstream media that enjoys a huge subscriber base/audience you will find a great deal of fabricated or sensational news because of biases and favouritism.

There is no such thing as ‘voluminous fabricated news’. Both words are adjectives and they can’t go together.
Now if you really must use those words, you can write:

In mainstream media that has a humongous subscriber base, you will often find a voluminous amount of fabricated news because of biases and favouritism.