It’s time to declare war on grammar snobs. They are both annoying and wrong:
The grammatical rules invoked by pedants aren’t real rules of grammar at all. They are, at best, just stylistic conventions: An example would be the use of a double negative (I can’t get no satisfaction). It makes complete grammatical sense, as an intensifier. It’s just a convention that we don’t use double negatives of that form in Standard English.
Some other pedantic stipulations are destructive pieces of folklore, like the belief that it is wrong to split an infinitive or to end a sentence with a preposition. We should be entirely relaxed about that sort of choice. Why worry, as some pedants do, about whether to write “firstly” or “first” when you begin a list of points? Either is correct.
The range of legitimate variation is wider than you would imagine. Yes, you may use “hopefully” as an adverb modifying an entire sentence; and you may use “they” as a singular generic pronoun; and you may say “between you and I.” The pedants’ prohibitions on constructions like these are not supported by the evidence of general usage.
Pedantry is poor manners, certainly, but also poor scholarship. If someone tells you that you “can’t” write something, ask them why not. Rarely will they have an answer that makes grammatical sense; it is probably just a superstition that they have carried around with them for years.
This is followed with a history of grammar snobbery that should make any grammar snob think twice about the “rules” they believe in.