I don't get why it's toxic.

They are designed in that manner to make them money.

Moreover, I also don't understand why people complain, you did not had money, so you asked banks for some, they gave it to you and are charging the interest.

I also don't understand the argument of students loan, you did not had any money to study, they gave it to you, and they charge some interest.

Over the years you might pay twice the amount you borrowed, but that's how interest work.