I think wider criticism of 40K is inevitable and a very good thing. It's a sign of the IP reaching for both multimedia and mainstream, and maturing into something that needs to stand up to critical appraisal rather than a boys club hidden away in plain sight (bearing in mind they remain a sizeable U.K. retail chain) after nearly 35 years.
GW has made great strides in recent years. Telling bigots to piss off and that they won't be missed, in echo of the famous 40K introduction. Bumping up the Sororitas to a full range and equal share in the spotlight for the intro to 9th edition. More diversity in who is represented on book covers, and in skin tones when the studio paints armies. More powerful heroes that aren't just white guys. More women writing the books (admittedly, an increase of 100% would still be a tiny minority, but Danie Ware and Rachel Harrison are always worth reading). They've still got a hell of a long way to go, and they could still do more to confront the inherent problematic elements of 40K, of which there is a long, long list.
I think them making it clear that they are a modern company selling a setting where everything is a perverse, terrifying mirror of the worst of humanity helps. But there are a lot of inconsistencies. Stuff like the novel protagonists tend to present Imperial characters as a good guy/force in a broken system, and rarely confronts the fact that they are all indoctrinated into a fascist death cult from birth. Like, you have to have flashes of light, of humour, friendship, heroism and romance or neither the mundane horrors of totalitarianism/fascism or the corrupts-everything-it-touches-if you-even-think-about-it nature of chaos body-horror mean much. But there is an issue when the setting itself is a broken nightmare of a galaxy but almost every single human protagonist remains largely functional and recognisable to us as 'heroic' despite GW hammering home how the rotting carcass of the Imperium in its death throes really isn't any better than those picking at it's corpse. And I think a publishing arm selling hundreds of books in that setting kinda needs to find ways to challenge that.
I've loved WFB/40K and the rest since the 1980s. I grew up reading 2000AD and the rest long before 40K coalesced it's influences into what it is today. And I think it's really, really healthy to discuss the problems and themes within it. It's big enough to take the criticism. It's changed in the face of it and it's so much better for it. But there's still a long way to go.
The uniqueness of the setting, that there's room for crime, comedy (I love the 'Big Brothers' comic strip on the community site), intrigue and horror away from the battlefield, the influence of the age of sail and any planet can be whatever you want for a story, means they created room for an IP they can do anything with. It all means there's room to improve where criticism of its failings holds water, and it often does.
I want to be able to play tabletop games with my daughter one day, and I hope criticism continues to push the setting into a fantasy nightmare galaxy where everyone can visit now and then and be horrified by it together. And where the Imperium is challenged by the out-of-universe writers for the awfulness that it is supposed to be, rather than sticking to rules and lore laid down when the core audience was very much me as a child and a handful of young white male writers thought that having everyone of any power in a tyrannical empire as a buff white guy demigod, and then making some of them the exemplars of all that was 'good', was a good idea..