Your review could have been removed for many reasons, but most commonly it was removed because it has little to do with the submission. The overall point of the NG review system is to discuss your opinion about a movie or game, either to the author or to others who might read it.
The review box is not meant for you to criticize the author directly, but rather just this specific work. The author is looking for feedback to what you liked or hated about this submission and stating how much you hate the author personally and threatening him or telling that he should not submit any more works is off point. Saying this should be "Blammed" or "this is gay" offers nothing to the author and often discourages them to stop making works. Newgrounds feed off user created content and being insulting to others is not tolerated.
Your review should not concern itself on whether it is on the front page or not. How is the author supposed to know what the Newgrounds staff is going to put on there? It is unfair to criticize someone for something they have no control over. The staff will often give exposure to authors they feel have potential and it is their call to whether they want to highlight it or not.
Your review should also not concern itself with other users' reviews. If you find a review that needs to be removed, flag it and it will be looked at. If you must converse with another user, then use the PM system. Newgrounds reviews system is not the YouTube comment system; your focus should be on the submission and not another users' opinion.
For things they do have control over like bugs, they really should be PM'ed to the author directly. If something is bugged then how can you give a fair review?
Common sense is welcomed when you are reviewing a submission. If a submission is blatant garbage, there is little need for it to have any comments. Insulting and giving attention to those who seek it will not help solve the problem. In addition, stating a submission is stolen helps no one and does not help to get the submission removed any faster. The only one who can do anything is one of the Newgrounds staff, contact one of them, and do not review it.
Do not be afraid of being critical of a submission, but do have some facts to back up why you are being harsh. What did you not like? Was the music terrible? Was the animation poor? Was it too short? Were the sounds too soft or too loud? These are the things authors are looking for and want to hear from you.
As well, do not be afraid of telling what you liked. You loved a submission, so what did you enjoy the most from it? Did the submission make you feel anything, like sorrow or humor? Was the submission original in its plot, etc?
Your reviews do not have to be overly detailed, but remember why you are reviewing; you are reviewing to express yourself to the author and to others. Giving good feedback that is relevant is important and is a privilege that is given to you. Make good use of it or it could be taken away.