You With Sword In Hand, Calm Yourself

The mental issues involved with subscribing to someone you dislike, hate, have anger towards, desire to ridicule or act maliciously, is very real and very dangerous. If you can not control your issues, then stay away from the people (on the internet) that trigger you so much. Unquestionably, if you call yourself a martial artist or play around with sharp 'toys', then it is dangerous to go along in life without growing up and becoming a better person than you were yesterday. If you want to be a nasty and mean cake decorator, be my guest. But if you're going to use and encourage the use of deadly weapons, then its best for yourself and the world community that you work on your character.
If the slightest hint of truth triggers you to the point of uncontrollable behavior, then its best you either put down your sharp toys or you try hard to work on yourself. If it means not associating with other toxic people who want to encourage bad behavior, then go off on your own. I am constantly working on my temper. It is hard. No high ranking sensei or monk is without their loss of temper. It is quite human, and we all have our fuses. Long or short. I have been attempting to lengthen mine for many many years. It would be nice to get rid of it but, that is a long process. I hope my tolerance is getting better over the years.

Calm Yourself

You can play in the sandbox until your dying day, or you can attempt to better yourself and go out into the larger world. Treat people with respect. When you offend someone, then you should apologize. When you can help someone to see the error of their ways, please do so compassionately and kindly. Start with the simple things;

Distance yourself from the people that set you off and cause you to act like an idiot.
Try to understand that the person upsetting you is the same as you and seeks love, happiness, and safety.
Investigate who is actually angry? 'I am angry' is not an acceptable answer.
Write out the email or comment but don't send or post it. Come back later or in a couple of days and look over it again. You might just laugh at how stupid it is to act on that impulse.
Understand that everything is impermanent. Yes, even that ugly thing someone said. It will not have the same effect later. In the end, it doesn't matter.
Reduce your time on video sharing sites or social media sites that excite your bad feelings.