My opinion is very similar to Ezequiel's, in that the rule book states that a red-card should be given for this type of tackle, therefore Rolland was within his rights to give a red-card.
However, my personal oppinion is that this was a yellow-card offense, and that's because it was abvious to everyone (or it should be), that there was no malice intended in the tackle. I feel that this matters in rugby, because it's a way of seperating blatant acts of malicious foul play (such as deliberately stamping on someone, gouging, full on spear tackles when the players head is drilled into the ground, and other such thuggery which is simply appalling), and accidental things like this and most high tackles which are something that happens in the heat of the moment. The length of the bans may differ, but that doesn't change the fact that it's cost the rest of the squad and the fans the game itself, and in this case a place at the rugby world cup final. Ideally, maybe a further card should be brought in, an orange which results in maybe 20-30min in the sin-bin for things like this and accidental high tackles etc. But intill something like that happens, then imo accidental challanges like this should be deemed yellow-cards, and if the citing board afterwards decide that more should have been given then they can hand out bans.
For the record, I'm not saying this just because he was a Welsh player and it probably cost us a place in the final. I personally feel that Rollands sending off of Fritz was a much worse decision.
So in the end, I voted that it should have been a yellow-card, despite agreeing that Rolland was well within his means of giving the red.