I agree that Robredo's style may seem boring, but - just like you said - he is 1000 times more entertaining than Karlovic or Isner f.e.
There are many kinf of players - ball bashers, master tacticians, shot makers, serving machines and people seem not to accept that and they bash all the players, whose style they don't accept. For me it seems that most of these trolls haven't ever played tennis and they don't understand the logic of it.
Tennis is a beautiful game, because we have such a diversity of players, playing with their own styles. And the key is to master your style. Karlovic will never win a rally with Nadal, but Nadal will never serve like Karlovic. And Robredo is the master of consistency, he has fantastic tactical feeling, is a great mover and runner. He isn't flashy, but is very solid and reliable and that's his style. You have to admire that, because in these departments he is one of the best players in the world and he mastered them to perfection. Robredo is a very good player, as these features I mentioned are the part of tennis.
And...I have watched Robredo's full match from the place for photographers, which is some two metres away from the courts. And I must tell you that he hits the ball really hard and is a very good one to watch, as all his shots are technically really well. I believe that if he played a "best of 13" match with 99,99% of MTFers - he would give a bagel 7 times, maybe with some golden sets included.
So no need to bash a guy, because you will never achieve the same things as him. Bashers are full of hidden jealousy.
Since when are you required to achieve similar things in order criticise someone? Come on, MTF (like any other internet forum) is based on opinions. Granted, some of them may not be fair, but that just comes with the territory. It´s not that serious, so just take it easy.