Bit of a stupid stance to take.
If they are good enough to improve our team's league position, we get benefit from it, and it is irrelevant if we are helping Arsenal, as they aren't in our league.
You've got a point, but it's a bit more complicated than that. He'll be keeping out one of our players (e.g. Lua Lua), who we should be developing, and then he'll return to Arsenal... leaving the real issue of our lack of quality still unsolved.
Don't think it's worth it to make the difference between finishing 13th and 11th, for example.