Taxpayers are not being forced to pay for the players to make their statement. If trump or pence want to fully fund the cost of the flight, the hotel, all the police on the road for the motorcade, the extra security at the stadium, etc, then make your statement all day long. 
Oh wait, you are only for protecting tax payer spending when it is being spent on actual tax payers.purple like you do not care at all of the money you see greedily protect is spent on frivolous things like golf or political protests.