Have you noticed that...?

Hmm... I think that there are a lot of poems that aren't "deep" but just badly written. Yes, there are some of the poems that you're referring to, that just need more reflection to grasp the meaning, but I don't think that there are that many of them. I do, however, agree with you that a lot of people do praise poems that even I (who isn't that good at writing poems myself) don't find to be particularly good.