No general statement will apply to everyone.
Some players have both and prefer the console for some things and the PC for others.
Some are kids and/or ranting clueless attention-seekers.
It seems to me that most often the console gamers claiming superiority are insecurely counter-reacting to the idea their consoles might be inferior, as some PC gamers sometimes remark.
It’s also a delayed mirroring of the bizarre decision by M$ to undermine their own gaming platform (Windohs) to try to push their X-Box product, and the obedience of the other game outlets in embracing console games rather than PCs, which occurred fairly artificially when the first X-Box was being marketed. That peculiar event brought with it some snobbery and herd-think language where consoles were supposed to be the cool way to play games now (circa 2000), and retail stores which now mainly sell console games still sometimes talk like that. But retail stores and many gaming journalists tend to parrot whatever their told to say, and a lot of that is driven by corporate marketing and the wish to have a standard platform to write to, and more control over who gets to publish what game for what platform, copy protection, less customer support to deal with, etc.
PC’s don’t get exactly the same content, as the console industry and some game companies still make some games exclusively for a console, sometimes not for PC, and sometimes screwed up when ported to PC (e.g. Dark Souls I). However there are also still even more games for computers than there are for consoles, and they tend to be different kinds of games. Even with the same titles, the different interface can make the experience quite a bit different. In first-person games, especially those where speed and precision is wanted (e.g. first-person shooters, where keyboard and mouse is far more precise than game controller, so the game has to help console gamers aim). There are of course also ports to PC that offer far more than the console version (e.g. Skyrim) and many games on PC that wouldn’t even work on a console unless you added a keyboard and/or mouse and/or high-res display (e.g. practically all strategy games or games that include typing), and games from indie developers, mods etc.