To be fair most frequently people online use debit cards which can be frozen if something goes wrong.
Uh, debit cards are the worse as they (technically) don’t allow you to dispute charges like in a credit card. Money comes right out of your account first, and then you have to try to get it back.
Don’t use debit cards online.
What good is freezing a card (regardless of debit or credit) after something has already gone wrong?