Why do so many people assume anything I say is so negative?

I've talked with a great many ridiculous people in this game. For example:

1. I tell them that the enemy support doesn't have a sightstone. And you know what they said about it? They explained how the enemy support was also ahead and that I suck and all that stuff. And you know why they were ahead? Because they didn't build a sightstone and you noob jungler refuses to gank them at all. I was just trying to give them a little hint that they'd be easy to gank.

2. I try to tell them that if they're just going to stand by the tower for 5 minutes then they should just recall. And they just screamed at me and never wanted to play bot with me again.

3. We're behind 8 kills to 7, and someone else on my team has also done really bad and they have an AP mid that's 4-0 with 16 Mejai's stacks. And then just because I said that we're behind, he calls me a troll and does a bunch of other stuff, too.

So, why must people be this way? I'm not trying to be mean or anything, but they seem to give me the anti-benefit of the doubt.