It's fair to observe that meanings of words change in practice, and the dictionary is there to document what words "do" mean, not what they "should" mean. However, a dictionary also plays a part in legitimizing new definitions, particularly in the early stages of when a word is being used in new ways. Look up the word "peruse" and you'll find two definitions that are effective opposites. I personally think that a word's meaning serves a purpose of concisely conveying ideas, and when you dilute meanings so that you can shoehorn a term into any space you want, you wind up destroying pieces of language and communication in the process. I don't think that "gaslighting" has been misused long enough to justify having a new definition that effectively cements the new meaning and throws away the ideas it used to convey. My hope is that the use of "gaslighting" to accuse anybody with whom you disagree of malicious intent (which is how it's come to mean any kind of deception) will eventually fade away as people find other terms to try to re-appropriate.

That doesn't change the fact that the provided definition is sloppy, and significantly deviates from the more nuanced, and long accepted definition. The parent commenter's point is still valid.