For example, this one had 1 upvote before it got downvoted. Did I post too fast, titles, etc or are riddles not allowed?
Riddles that follow the rules are totally allowed. While those rules are currently being formalized and will continue to change, here's a good guideline for now. There are those on the site that feel we should only talk about puzzle theory. Some of them serial downvote puzzles themselves. Other times, it's that someone just doesn't like the style or feel that the quality is up to par. I've got a riddle that's over +50 right now, but it started off in the negatives. It's just part of the game. Don't get discouraged.
I didn't see the riddle and didn't vote on it, but I would guess it's been downvoted due to an apparent lack of effort. Riddles are very much welcome, low-quality anythings are not.
The lines don't rhyme, they have no meter (di-dah di-dah di-dah, di-dah di-dah di-dah) and personally I feel that it's a bit too obvious (note: I don't think overly-abstract riddles are good either - balance is important).
That said, don't let it dissuade you. Look at other riddles (maybe not from the last 2 days) and you'll see they flow when you read them. Try to copy that, and don't forget you can always post a riddle, give the answer (maybe in a spoiler tag) then specifically ask How do I improve my riddle? to get feedback from people who are more into riddling.
Don't confuse down-voting with voting-for-closure (or hold). While explanation for votes are encouraged it is not obligatory (but sensible voting is not yet established in the community as a whole).
Asking for the reasons of a down vote might be futile, as the person giving it most likely never reads your question (or cares about.) Also, votes (up and down) change. If you receive many down votes, there is obviously something not quite right - or your puzzle/riddle has not yet found it's fan group.
Either way, if your posted puzzles/riddles are voted for [closure], then there is likely a "not suitable for this site" reason. If it is purely down voted, some / many people just don't think it's a good riddle. Opinions are free.