They must be legal though, otherwise they'd get shut down. I'm not talking about instant exchangers but any kind of centralized exchange, in general. They basically all have such a clause.
I'm talking about small exchangers. Thay have malicious terms and don't get shut down because in Russia it doesn't work like this. In Russia you don't get shut down if you have malicious rules. I mean, normally nobody cares. As for big centralized exchangers, in their cases rules about blocking funds are inappropriate but aren't malicious and aren't against the law. Because they are legal registered companies. So you can sue them, they have duties etc.
You are trying to get instant exchangers offline by pressuring the hosting services that they use?
In my opinion, that doesn't solve the bigger problem, which are the actual centralized exchanges behind these services.
I don't want them to shut down. I want to show them they must respect customers and must remove crazy rules. The community doesnt't want these rules. And this would solve the bigger problem partially. If small exchangers stop to use big centralized ones and start to use noncustodial wallets for their coins, the part of the bigger problem will be solved.
That's where the largest sums of money are 'stolen'; people depositing whole coins and getting them confiscated.
In this case I think "both parties agreed" works
Because as a legal financial organization a big exchanger unfortunately has a right to confiscate funds. In fact in this case funds are confiscated by governments with help of big exchangers. But when someone registers on a big exchanger and then puts his coins there he expects his coins to be reviewed and maybe confiscated. Because in this case it's pretty much like putting your coins in a bank. Big exchanger's users are well informed and agree with this. They accept this because want the government to control their financial operations and want to have guarantees a big exchangers gives them. I know these guarantees are BS and it's much safer to use a noncustodial wallet but many people don't agree with that and consider Binance a safer place to keep coins. And also many people think governement control gives them safety. It's their decision.
Why would it be illegal for small exchangers to confiscate funds (and write it in their terms), but legal for the big ones?
Because of different legal status. I explained this above. The difference is a big exchanger is a legal registered company, it has duties and responsibility and acts according the laws, provides you it's legal data so you can go to court etc. That's why a big exchanger has authority to block funds. And a small exchanger isn't a company, it's some anonymous guy. He doesn't give you any guarantees, doesn't have duties and doesn't have any authority. So he wants to stay anonymous and have zero responsibility but he doesn't want you to be anonymous and can just take your coins.
It's like asking "if police can detain people why some random guy you see on the street can't?". Because there is a difference
Even if you get all the little ones banned, people will just lose their money to the big ones.
I'm not people's nanny
Also I don't want small ones to get banned. I want them to work like normal people and according to their legal status. They can't demand from clients anything they want. Or both a customer and an exchanger stay anonymous (and in this case nobody asks for documents and nobbody blocks funds) or both give personal and legal info to each other, exchanger gives guarantees, has authority to block funds and does it legally etc. But it can't be like "I stay anonymous and work illegally but you give me your docs and I block your money".
That's why I believe showing them the alternatives is much more important. If they get it, the market will decide, i.e. centralized exchanges with shitty terms (big or small) will have to change course to stay afloat.
Showing them alternatives is very important. But it doesn't mean we just should accept anything small exchangers do. Both things are important. And also as for small exchangers if many people knew how crazy their rules are I think the market would decide to get rid of them very soon. The problem is nobody can't even imagine some random anonymous guy puts in his rules he can confiscate your funds.
which made me think that all was good, but seeing your comments here made me think twice now, thanks for the heads up 
I've been doing the only thing we can do against this, for years; which is informing people about these practices and recommending alternatives.