Even to an arch anti-federast like me, this just seems dumb. At this point in time, the Ukipers should be guarding their precious powder, not letting off fireworks.
The only defence (other than it's the truth) is that Schutz is just as bad, which is a playground defence really. A player can get sent off for fouling, and it's not relevant if the player he fouled had fouled and got away with it earlier, and Bloom would better serve the team by staying on the pitch.
The Euro 'Parliament' is essentially a joke, that much is true, and it's not easy participating in it when you don't accept it has a mandate to do anything. Nevertheless, there is an argument in favour of sticking around to mess things up and be a nuisance, but you've still got to try to do it in a way that makes them look bad, and not yourself.