When you think how much Hamilton has matured in such a short time. I have seen no such development from Vettel.
Hamilton may go on to become one of the all-time greats, possibly breaking most of the records which MS set. To compare any (newish) driver to Hamilton, is a little unfair.
Vettel is "learning" his trade at the front of the grid. Hamilton also did this but, like I said, he is probably going to be one of the all time greats.
Remember, even MS, who IS THE all time great, had a few seasons where he learnt his trade, without being at the front of the grid. When he hit the front in a title winning car in 1994 (after joining F1 in 1991), he had learnt a lot, but was still rough around the edges. In 1995, he came of age and was the complete package. In effect, he needed about 3.5 years to master F1.
Vettel may not be as good as Hamilton or MS and thus, is likely to make more mistakes and learn at a slower rate, than those 2 drivers. To direct 4 letter words towards him, because he made a mistake, is unfair.