Can someone tell me what the deal is with trading lately?

I play TF2 on and off. I first picked it up in summer 2010 when the Orange Box was on sale, and played it a lot then, but after that point it's really been on-and-off. Like, whenever I need a break and I want to play something that's just legitimately fun.

But lately, whenever I pick up the game, I've been experiencing an interesting problem. It's probably best summarized in this rage comic. (I was going to post it in r/tf2, but I realized I was genuinely curious about this phenomenon and wanted to ask for advice about it more explicitly, because there's more to it than just "it pisses me off.") The problem is trading. I guess I wasn't around when trading became a big thing, but lately, I can't get two minutes into a game without getting trading requests from basically every other player in the game. Even when I tell people no, which I don't feel I have to, I keep getting bugged.

I don't do the trading thing. Not to be cliché, but I'm a man of simple pleasures - I don't like complicating things any further than they need to be. One of the reasons I like TF2 so much is because it's one of the only games that, I think, is really just fun, above all else. The lighthearted insanity of it all and the colorful visuals just make playing it a really fun experience. So I don't really like to complicate it much more than that. You know, if I get cool stuff in drops or through unlocks from other games or whatever, cool, but I'm not gonna go through the effort to like, craft stuff, or trade stuff with people - I just wanna have some fun playing a dumb, fun, silly game. (This is not a criticism of TF2, which is obviously awesome. But I enjoy just having some dumb fun.)

So when stuff like this happens, I'm obviously a little taken aback. I don't like having to stop playing just to tell people I'm not interested in trading (I don't use voice chat, so I have to type it all out), only to have like ten other people, if not THE SAME people who already asked, request trades again and again and again throughout the match.

So, r/tf2, I ask you - what's the deal with all this trading crap? Is there something I'm not "getting" about all of this? Why is it not "okay" that I'm not interested in trading with people, and what should I do to prevent having my TF2 experiences muddied with this kind of crap?