Surely something FR do with regards to passengers getting on their planes is different to a country deciding to treat a certain companies crew different to all other carriers using their main airport?
As for the visa checks... All airlines need to check for these, there is no time to do so at the gate as it requires a few minutes to do it properly, so FR demand you do it before coming to the gate. Quite a simply process. Turn up to an FR desk, get it looked at and they stamp your boarding card, gate staff see the stamp and let you on. If you can't be bothered sticking to the terms and conditions you agreed to when you bought your ticket then why should FR up hold their end of the bargain too?
Jet2.com are another airline which demand a visa check is done before coming to the gate, so it's not even an FR only policy.