Of course that's what we'd all chose to do if possible, but on what grounds?
Remember these people have been sold tickets, been checked in (therefore a contract exists with them for carriage). They've been through the full rigors (!) of airport security (in a major euro airport) and have behaved themselves impeccably (so far).
They have also done nothing illegal...carrying nasty literature is not a criminal offence!
So on what grounds do you off-load them?
Pure prejudice?
Would your company back your actions when they sue?