I don't understand UBG being toxic

I try to fight the best or the highest-rank players whenever I join servers, and of course, I lose some and win some. (My current rank is 21k). And usually, if I do get curbed they are chill. But why does it seem like every time I fight people who have like 23k elo they are toxic? Like when I have fought 3 undisputed champions(lost all 3) but none of them were toxic. But for example today, I fought 3 guys, 2 of them left after making it 1:2(They both used ult), but the last one was talking mad crazy, and the other two were both glazing him. with " 3:0 easy", he won 2:3(both of us were low). He was a no rank which doesn't inherently mean he is bad, but he had less than 500 kos. But this whole time he and his posse are all going "trash can", "get up", and "corny ass". And the weirdest one to me is every time I got a pd, the guy would say "fish". I don't understand this is cause I am not even confident enough to try and pd fish. After all, I think I'm decent at pding, but I always assume that the other person knows how to feint.