I am at daily atm as I was medicated and joined a heap of tournaments lol, not i have insane amounts to play.
Why are half the people on this site afraid of a rematch?

If you attack too aggressive or too defensive, they mightn't play with you. But if you attacked brilliantly or some moves they didn't expect and being surprised, they might try to rematch with you for learning purposes or try to beat you or by excitement. or even afraid of losing more trophies There are various answers to your questions. Humans' answers cannot be shortened down to few reasons.

Disgusting cowards
Why do half of the players on this site have their ego so tightly wedged into the outcome of a game that they cry like a little girl whenever they lose and can't immediately "take revenge".

Usually I reject rematch unless the opponent has shown something really impressive. I play for pleasure, if you wish to prove something do it with someone else.

if my oppoment plays a respected opening and not some boring system opening or some dubious try for a win then i usually rematch
i also take a look at their rep before i accept the rematch, ive saved myself many times from being bored out my mind agianst the london system or the bowdler sicilian

Disgusting cowards
You have played 50 or so games since joining this site earlier this month...and are raging about rematches. There are many reasons why players wouldn't want to rematch, many have no malevolent intent.However,in your case it may be players don't want to deal with the likes of you.

When you lose, instead of clicking the Rematch button, spend your next few minutes reviewing your game, to try to learn from what you did wrong.
Disgusting cowards