Why's that? It doesn't seem like something I'd consider a default for someone called a "fighter." Being good at all physical interactions is nice, but I don't think social interactions should be a default focus for the class.
They're called "fighters" not "talkers."
Yeah and Sorcerers are called Sorcerers, not "talkers", and so on. We can play this game with all the classes except maybe Bard.
Fighters should at least have an option for better social abilities. But they don't, because the default Fighter design basically attempts to revert to 3.XE, and gives Fighters extra ASIs/Feats instead of extra abilities. And Feats aren't a great substitute for abilities here, because they tend to just grant you the most basic level of proficiency in a skill, like you'd get from a Background.
What makes you think my fighters aren't social if I want a social fighter? It's silly to force fighters into a social pillar when a player can build that way by choice.
They can't actually build to be good at it, in default 5E though, unless they have rolled stats and CHA to spare. Assuming they need STR or DEX and CON as primary and secondary (and they pretty much do), with other stat methods, whatever is left for CHA is likely to be pretty low, and then all you have is maybe Persuasion and one of Deception or Intimidate.
And any CHA-based character is going to do nearly as well untrained, and better if trained.
What makes you think the bard is foppish instead of grizzled too? The bard can have a soldier background just as easily as the fighter can have an entertainer background. ;-)
Uh-huh, but the point is, under D&D 5E's actual rules, the foppish Bard is going to have a better chance than the grizzled Fighter. In a lot of other games, that wouldn't be true. In some, it would even just matter mostly whether you were grizzled or foppish, and your "class" or equivalent would be irrelevant.
I've don't consider them these heroes from fairytales, I consider them superhuman mercenaries.
That's an incredibly bizarre and specific take on what a D&D Fighter is. Particularly the idea that Fighters are "mercenaries", but other D&D classes aren't is just outrageously weird. Indeed most are also superhuman.
An important part of the CHA stat is finding ways to relate to others, and get others to relate to you. If you want your fighter to be relatable to people in your world, just don't make CHA your dump stat. Problem solved.
Not really though, because 5E is a party-based game, and in most parties, some other PC is going to be better than you at social stuff. To compete you'd have to make CHA your primary, making yourself actively worse at fighting. And 5E encourages you to have the highest person roll, and another assist - and you gain zero benefit from the person assisting actually being good at the skill in question.