It's important to say up front that a downvote is not a judgement of you, it is a judgement of your question or answer. A downvote means the downvoter thinks it is not a suitable question/answer for this site, and that's all it means.
Well, in theory. In practice it is very hard not to take downvotes personally, and I hate being downvoted as much as you and everyone else does. But everyone who posts on this site attracts downvotes sooner or later and you just have to decide whether you can live with it or not.
(Incidentally I've had my share of rude comments too, which can be even more upsetting. If someone makes a rude comment to one of your posts that's not acceptable so flag it and a moderator will delete the comment.)
But to return to the point, if you've got a downvote on an answer you need to have a think about whether your answer does need some improvement. Most of the prolific answerers here regard the site as a sort of encyclopaedia of physics. That is, a physicist, physics student or anyone wanting to learn physics can look at a question here and be confident that the answers are clear, concise and above all unimpeachable. You should be able to treat anything written in an answer here as gospel truth.
That means answers need to conform to certain standards. We aren't keen on answers that just link to some page on the Internet because that link could break and anyway we have no control over what's at the other end of it. I would guess that's why this answer of yours got downvoted, because it's just a link and a few comments.
I'd guess the cat post got a downvote because it's anecdotal and the anecdote doesn't address the question - though note that that answer got two upvotes as well.
I can't see where the third downvote is but looking at the two example above I would say the downvotes are justified and you should consider the criticism they imply. It would be nice if downvoters always left a comment to say what aspects of the answer they don't think are good. But to be fair not all answerers respond positively to comments and it can get quite nasty - discretion is sometimes the better part of valour.
Finally, it can be hard for newcomers especially if they're at an early stage in learning physics, and many of us will bear this in mind when we vote on a question or comment on it. But we don't lower our standards, not even for newcomers. At the end of the day a newcomer's answer is judged by the same standards as answers from veteran site members. It's up to you to be sure before you post that your answer is clear, concise and above all correct. If you aren't sure about this then you should think carefully before you post.
A quick footnote:
A great many people have dedicated a great deal of time and effort (for free!) to writing some great answers on this site. Some of the explanations here are staggeringly good and far better than anything I encountered as an undergraduate or PhD student. By titling your post here Snobs and down-voters you are tarring us all with the same brush, and frankly that won't win you any friends.
Lastly note that here on the Meta site a downvote just signifies disagreement. So the two downvotes (at the time of writing) that your question has attracted just mean that two people disagree with the sentiments it expresses.