I don't know how curious it is. The people who "create" these things don't have any imagination. So they see a version and think, "Hey, I should do one too," and the next thing you know there are twenty or thirty or five hundred of them.
The number of versions probably has less to do with the poem and more to do with the viral effect of sticking something up on the Internet. The first person to make one of those videos obviously had a fondness for the poem. But the idea that several people - independent of each other - were so moved by a poem in a 20 year old book that they were compelled to make YouTube videos is more than a little...implausible.
In case you didn't notice, Bluebird has been quoted a TON lately in interviews. At least it is REAL Bukowski and not a false attribute, but it seems so (ok I don't want to say Gay because that is just plain lazy)... so Gen Y or Millenium. It's a great line and if you know Buk, in the appropriate context, very powerful. But as a stand-alone verse without context... well I know plenty of Dykes who would think that was pretty sappy... and they'd be right.