Isn't your teacher lied to you ?
Isn't your teacher beated you for no reason ?
Isn't your teacher get angried to you without a proper reason ?
Isn't your teacher used you and then didn't minded you ?
Isn't your teacher give too much punishments to you ?
Etc…
But still why ?
(Am not asking this to criticize anybody or disrespect others. Just a doubt formed in my mind as a student. If am asking anything wrong please correct me)
There's a difference between respecting someone and treating them with respect. True respect has to be earned, while everyone should be treated with respect by default (until they give you a reason not to).
If your teacher is an asshole, depending on your situation, it might be in your best interest to act as if you respected them for your own sake.