While language does evolve over time, we shouldn't encourage unnecessary and somewhat negative evolutions of it, and especially not encourage it to change over less time.

When two previously distinct words come to have the same meaning, this can be a problem. First, older written things become less comprehensible. Few of us today could read and understand old english because so many words have changed. The evolution of language has taken a long time to get to that point, at least. But if we encourage the acceleration of this change, something which appears to be happening even without encouragement, how long will it be?

Today, we can still pretty clearly understand things written 200 years ago; some bits are confusing but for the most part it is still clear. If language change accelerates enough, in the future, people may struggle to understand something written only a hundred years ago, or even less.

The second problem is that if the word for a thing goes away, it becomes more difficult to express that concept. Consider the word 'literally' whose meaning has become extremely muddled. In order to express the original concept, we now require additional emphasis. There are other, more difficult to think of terms like that - a concept for which a particular word would have been perfect had the word's meaning not significantly changed.

So when a word's usage is corrected, do not be so quick to defend the misuse of the word through 'language evolves!' If people accept that 'oops, I used that word wrong' and then see if there is already a better word for what they were trying to express to correct themselves with, that is probably better - in most cases.

Even more notably, new words should be used when possible, if an older word doesn't quite fit a newly emerging thing, or even a concept that has existed for some time but has not had a word to describe it precisely. One of my favorite examples of this is the word 'cromulent' which expresses a concept that did not have a specific word for it in common use at the time, even though the concept of 'understandable and linguistically correct' certainly already existed. Also consider the now common word 'emoji' which was coined specifically to represent this concept. This is an excellent evolution of language because it took nothing away. It arose in response to something which did not exist, and described that thing with a word created specifically for it.

That said, fighting against the evolution of language that has already happened and is far too entrenched to ever change is nonsensical. My father, for instance, insists 'cool' should be for temperature description only, even though that word possessed its non-temperature meaning before he was even born. Similarly, sometimes the change is resisted for bad reasons; like the word 'gay'. In these cases, it is best not to try to fight the change, but instead embrace and encourage it.

So ultimately, when a word is used wrong, consider whether the word evolving to the way it is being used is a positive change. If it does not make things better, it's probably best not to encourage it.