This makes no sense at all to me. If you're getting 2-3 people a day following you, and then sending you hateful DMs when you follow back, you seriously keep refollowing random people who will presumably be harassing you? It's not punishing anyone to put a bit of an effort in to seeing if the person seems legit before following them back.
If you have 20 new people a day following you and 2-3 are trolls, I'd still do it. No troll is going to make me change my polite behavior with other people.
I'd even go so far as to say that if you don't care enough about the person to research them before following them, then you shouldn't be following them anyhow.
