Nowhere does the comic say anything about trading, pings, or anything other than no voice chat, text chat, or friend requests. I don't know where you inferred that from.
I agree with the comic about how stupid the argument that multiplayer games are more meaningful is when people turn all that stuff off first thing; however, as a girl gamer, I turn off voice and text chat and friend requests immediately in a game because I don't need to be harassed while I just want to play a game. But there's plenty of other ways to interact with players.
Take Dark Souls, for example. Famous for its asynchronous message system, but lacking any voice or text chat when you're playing with other people. Your only forms of communication are any emotes or a handful of items that emit a stock phrase (like "hello" and "help me") that you might get during your playthrough, and your in-game actions. This has led to the common friendly Souls greeting of...spamming the L1 button to wiggle your weapon back and forth. Or if you walk up towards a corner and pull up your shield, people might infer that you're warning of an ambush around the corner.
Like seemingly everybody else in the world, I've been playing Helldivers 2 recently, and despite that game having a ping system, tagging of enemies and points of interest, stock phrases like "follow me," and emotes, the most common interactions I've had with people have involved players just randomly diving into each other and running around in circles.
Without language, people will always find ways to interact with each other. And just because you're not speaking with somebody doesn't mean that they're not enriching your gaming experience.