Ever read any court decisions? Laws? Grammar matters. Consider the difference in the two sentences.
Please do not call out users in the forum or chat. Submit a ticket in the Support Forum.
and
Please do not call out users in the forum or chat, submit a ticket in the Support Forum.
One is a complete thought, one is two separate thoughts. In your example you provide two contradictory thoughts which works just fine grammatically, but the intent of them makes the two contradictory. Intent matters, and if you don't understand the difference in the intent of a comma vs a period, it will be difficult for you to argue semantics.
Also, semantic rules say you should capitalize the first letter of a sentence, so look to your own.

you can express one complete thought in two sentences separated with comma as well as period, there is no rule telling me that i have to completely express my thought within one sentence before ending it with a period mark. also worth noticing would be a fact that i do not capitalize anything in my posts, so i beg to differ about that argument you made - the fact i don't doesn't mean i don't know where to apply such simple rules.

Wont let me reply to your last post. Are you really arguing that intent in sentence construction doesn't matter? Why argue against the intent of the author? If CG wanted it as a single idea, he would of written it as a compound sentence. He didn't. They remain independent. Are you really saying that, "Hey lets eat Grandma!", "Hey lets eat, Grandma!" and, "Hey lets eat! Grandma!", are really all the same idea? That's why we bother with punctuation, because again, intent in sentence structure matters. CG separated the two ideas, "Please do not call out users in the forum or chat" and "Submit a ticket in the Support Forum." to give two different directives. No calling out users, and that Support is where can try to hash out any problem you have with a person. Obviously if the mods cant do anything there is no reason to, but still there remains that you cannot call out someone else on the forums. In fact the person, not being on SG, probably wont see the thread, and so will not have any chance to defend themselves. We have an etiquette for the forums, and that means no baseless accusations, or outing of problems with other people. There is a place for that, SteamRep is one, but CG doesn't want that here. Stop defending a guy who wants to post unproven allegations about someone not even related to this community.

"...the fact i don't doesn't mean i don't know where to apply such simple rules."

No, it means you communicate poorly.