Why would the winner of a game chat 'loser' at the end of the game?

OK so this has happened to me a couple of times (though it is very infrequent). Just so you don't think I am doing something to warrant this here are a few details of the last game in which this happened ...

I would link the game but that would be calling out a person and I don't want to get into trouble. So I am around 1400 and played a 10+5 and I was black. I play a KID setup. The game went into the end game and he was able to trade everything and he was a pawn up and his King was in a position where I couldn't prevent him from taking my pawn and his pawn was on the 6th rank. (I am somewhat weak in the endgame). So I resigned because he was going to Queen a pawn and frankly I'm not one of those guys who plays to the last move. I know other people do that but that's not my choice. When its going to be a Queen verses my King I usually resign. (But if I have pieces on the board I will play on).

So no chat took place during the game and at the end I resign and noticed he chatted me. I look and he types a single word "loser".

The reason for me typing all of this is that I just want to understand the mentality behind this. I personally don't come here to destroy the opponent and make them feel terrible. Its a board game. LOL. It's competitive and yet also (hopefully) friendly. If you need some avenue where you build yourself up by putting down others, then that's a personal problem.

Does this happen when the player is a child? Are adults doing this as well? Do you do this?

Anyway, what are your thoughts? (And it would be super great if you didn't flame me).

i actually looked at your recent loss........ people chat "loser" when they're insecure jerks. i just block 'em. unless i feel like chatting them back, but that's generally not worth it unless i'm super duper bored and feel like swapping insults. you could always turn chat off. and personally, i think you're right to just resign. when guys just shove wood all over, in spite of overwhelming odds, people might give you shit. no, i don't do this --- the only time i talk shit is stuff like 'lol' 'oh oh' etc when they disconnect. but sometimes they reconnect and then i have to go 'oops' or the like.

@pawnmulch Thanks. Yeah I turned off chat except friends. I didn't think to do that until now.

Why would you want to "understand the mentality behind this"? That's like when a carton of milk is a month overdue, you still have to stick your nose in there and take a whiff...

And incidentally, wait'll you win and you still get guys typing "loser" (or more likely, "looser"). ;)

@MrPushwood I don't see how your analogy has anything at all to do with my question.

Actually,I don't remember last time someone sent to me "loser" in the chat,but probably it is very uncommon thing,if ever happens.Most of the people are nice enough usually.If you see such behavior,use lichess.org/report button.Mods are going to always help out in these situations :)

@inmaniac, just don't think about it too much! like in the real world, there are some really kool people, a lot of nice ones and some idiots around. you won't change the latter... play whatever you like and enjoy the games and chats :-)

I suggest two options
1. Report (as abuse/bad manners/spam/etc.) and block.
2. Turn off the chat.

There is no use trying to chat to them. They already made it clear who they are. Fortunatelly in chess community we don't have many bastards. They quickly get banned.

There are lot of people here, that are insulting. This week i played a game where i made an opening trap and my opponent fell for it. Because he was so salty and his ego got destroyed, he typed "fuck you" in the chat.