TBH i really appreciate it when someone tears apart my pictures. I can make up my own mind about if they are right or not, but usually it offers some insight and helps me improve, so I see it as a gift. Even if I don't agree with it, it helps me understand how others perceive my work and that could be beneficial. On reflection, it's when I have been told the harsh stuff in a direct way that I have been able to make a big leap forward. It sticks in my mind when I am out shooting again and this is why I use the "critique" tag on all my image posts.
There are a lot of threads here condemning people for not being subtle in their critique, or maybe delivering it in a way that could be taken as an insult. I don't really mind how it gets delivered (this is a public forum after all, so you should expect all sorts), at least they felt compelled enough to offer their opinion.
Personally I always try to highlight the good points, along with the bad (delivering the classic "s**t sandwich"), but admit it is difficult at times. It's not always possible and sometimes you can only focus on the bad points. On the flip side, I will resort with a "nice pic" comment if I can't find anything obviously wrong that hasn't been previously mentioned, just as a nod to say I've spent some time admiring it. I certainly don't expect everyone to adopt this approach (and it would probably be a pretty dull forum if they did). Anyway, some people just like looking through the posts without participating and that's fine too (so don't worry about the number of views).