So he didn't want the blame if spurs lost due to red cards. Two things.
1) What if they then went on to win. That would have had an effect in itself.
2) As mentioned above, players would have had suspensions and them not being suspended could also have had a huge effect. Heck perhaps even not sending them off had a knock on effect, who knows?
Clattenburg and others need to ref the games they are in according to the rules and not some game plan because other games/teams could potentially be affected through no fault of their own.
We have a similar thing in ice hockey here, you hear commentators saying, "oh well Montreal have had 3 straight penalties (meaning they are being penalised), he's not going to give another". If they are breaking the rules then they deserve it, you now have a situation whereby Montreal can cheat without fear of any punishment.