Umbridge? Abusive. Carrows? Abusive. Snape? Occasionally an asshole and dick but still did the right thing in the end. Reread the books with a clear and objective mindset, if you're capable of such. Until then? Your Snape hate is based on out of context extremes and sjw catchphrases that don't even apply to his character.
Remember that one time he threatened (and actually tried) to kill a student’s pet?
Remember that one time he made fun of a student’s appearance, prompting her to permanently alter it?
Remember that one time he physically threw a student to the ground because he was embarrassed?
These kids are under his control and he is terrorizing them. He is, quite literally, abusing them.