How is that people get pissed when you decline a request of move withdrawal?

Because they're whining little babies. Life gives no takebacks and chess neither.

why you have takeback enabled in your settings?

@petri999: I didn't even know that it can be disabled. thanks for the info

anyway, I'm not against the possibility to ask for it. I just don't understand why people get pissed when is not accepted.

I get pissed if it was an obvious misclick, but other than that, meh

Sometimes, they're pissed because they can't stand losing a game (see how many players prefer being banned rather than resign a lost game).
Sometimes, they say it's an obvious missclick, even if it's not, and say if you really loves the game, you have to accept the takeback.
Sometimes, they don't care about the game but it's a good opportunity to be a jerk.

My Lichess experience is much better since I disabled takebacks.

Take backs are fine in certain game situations...but to ask for a take back in a rated game... Never!. I myself... never ask for take backs. Funny thing too...As an experiment during one game I was playing, I granted a much weaker opponent, a take back, then a few moves later I purposely dropped a piece and asked for a takeback...He said there was no way. Ain't that something! :]

@Skittle-Head Purposefully dropped a piece? LMAO. There's a difference between a misclick (deserves a takeback) and someone making a blunder (doesn't deserve a takeback)

@MyBrainIsMush It was an experiment...non rated game :]
My opponent failed to return the favor...I lost all faith in mankind :]
And as I said takebacks in rated games..."even for midclick's" I think that it should be built right into the software... that when a rated game is being played...The take back button should disappear. :]