Compared to other sites (LEGO and non-LEGO related) Brickset is actually very good on not having too many '1st comment!!' comments. I have seen many sites where it is nothing short of ridiculous, with several variations of '1st comment!', some then edited when they find out they aren't, and then '2nd comment', '5th comment' etc!
The comment in question is the first I have seen in a good while. Off topic comments are usually deleted very quickly, but the one that you object to was in fact partially on topic, so I really don't think it warrants a measure as severe as a temporary ban.
I quite agree that we do not want Brickset to degrade into the shambles I described above, but I have to say that this really does not seem like a big enough deal to create a major objection to. It's not as if this particular user has been consistently commenting on every article with '1st comment!' or variations.
Please rest assured that if repeat offenders are identified the appropriate action will be taken.
...point out to people who've made lengthy posts without proper punctuation or with lots of errors how they should take a little more care but other then that, how is it helpful to make people feel bad about making a mistake?