As a new member I don't get the "take back a move" feature.

Hi, I recently joined this site after having my chess passion (re)ignited from the many twitch streams.
I play 5+3 games in workbreaks or during meals and it feels like a great midway between not having the time to think at all and beeing forced to grasp every detail of my next move.
Something I stumbled upon is the "request to take back the last move" feature. Isn't the point of faster chess or maybe chess in general, that at some point one player oversees something and thus the advantage of the other player starts to snowball?
It feels like in every third or fourth match and most of the matches I win my opponent wants to take back blunder. Following that stated logic I decline.
Is that considered bad manner here?

I allow a takeback if the move is an obvious misclick, but it is perfectly fine to decline all the time especially in short time controls.
There is an option in "Preferences" to disable the option so that you will not be bothered by the message.

Ah thats good to know. I'll use that.
In the first matches I tried to follow a similar guideline, but in my elo (950~) it's hard to differentiate misclicks from oversights :D.