I used to agree with him on that point, I've even defended him in this thread, but gatekeeping's looking like a mighty fine idea given the number of franchises and fanbases that have suffered brain drain from...immigrants.
Accessibility is a double edged sword, and when wielded by the ignorant, it only leads to them hurting what they're trying to protect. 'Good' accessibility is making the complexity or the difficulty of a gameplay system more understandable, particularly in the edge cases where there may be a mismatch between what the player thinks and what the game thinks of the rules, and providing information to bridge that gap. Example, the old Thief or Splinter Cell games providing a light meter for stealth, helping make it clear if the shadows are dark enough to hide you. The enemies in those games tend to be aware and alert and will easily spot you if you're out in the open, the game just provides a bit of concrete information about your current location to know if its safe or not. You still need to plan out your moves and pay attention to not get got.
'Bad' accessibility is when complexity or difficulty in a gameplay system is removed because some portion of players cannot get good enough to deal with it. Modern stealth games have replaced providing information about how visible you are and relative risk to intelligent AI with a simple indicator and fill bar. There's a bunch of visibility rules and conditions and such probably being run, but none of it matters because its all boiled down to "spotted bar fills up" and you never have to actually engage with stealth, you just have to know "If bar filling up, go somewhere else or don't do that".
This is were difficulty modes get maligned, as they usually err on the side of bad accessibility. Easy mode rarely provides more information to the player or reduces the complexity of encounters, it just hits the enemy with the nerf bat, and now they're blind and impotent and there's half as many of them. Hard mode rarely increases mechanical complexity or reduces information, it usually just makes the enemy a beefstack that soaks damage and hits harder. Rather than leading to mechanically distinct experiences where the mode selection varies how the gameplay is engaged with, it just shovels some numbers to decide how punishing the mechanics are, rather than how engaging they are. The difficulty levels in a Call of Duty game are a shining example of this, where enemies go from unable to shoot straight while firing .22's, to 360 noscoping you while killing you with one or two shots as you progress up the difficulty curve. There are no mechanical changes or systems, and the only real reason to turn up the difficulty is if you find the particular pace of a fight too boring without it.
A good example of good Difficulty and Accessibility in the modern era might be the Metro Ranger difficulty modes. In Metro, the ranger difficulty increases gunfire lethality across the board at the same time that it reduces the availability of resources and the hardcore version strips out the HUD and other non-diegetic UI elements entirely. This makes the existing diegetic mechanics for stealth and combat and environmental navigation much more important to engage with, while also rewarding smart stealth and combat play via increased lethality if you shoot well or get the drop on someone. This ultimately rewards the player for engaging with all the gameplay systems as designed and intended, without just allowing you to ignore some because its too much of a bother to learn the details for. Both forcing engagement and rewarding mastery is a hallmark of a good difficulty level, as one might see in a souls game.
Also, I've never played Dragon Age before but I suspect the monsters didn't always look like generic WoW knockoffs?
Depends on the monsters. The Veil demons and whatnot were always fairly generic, and the Darkspawn were more or less Uruks, but it worked in the grittier tone the early games had.

Nothing to write home about, but it worked back when Biowares strength was writing interesting narratives and worlds, the Darkspawn fit well into their place. Not so sure about the modern incarnations of this shit.