All the people that i know "act differently online" - compared to their real life version. And there's people that i know on a personal level since childhood - who seem more or less like strangers while texting. They have different vibes as well (they feel different). The differences are not always that huge (in some cases you can see a resemblance) - but sometimes is like talking to different people altogether.
This is not a Gemini thing. It's people thing. Real life people and their cyber version. Take your nickname (I_Hate_Tomatoes) - and your avatar for example. 🤨 Does that reflect your real life version?! I can't say much about you - from what you wrote so far - cause you're just venting. In a different context you might behave differently.