I'm not hating on Linux, I have just used it totally as my daily driver for the last year, I prefer it and would go back to it as I said but I actually need the speed and quality that Lightroom and Photoshop afford.
They cannot currently be replicated by FOSS alternatives unfortunately.
Partly I think the UNIX philosophy gets in the way slightly, as Lightroom offers both catalogue, RAW development, printing, book creating and galleries in one place. This is important as when you manage multi terrabyte catalogues and hundreds of thousands of photos, having a single tool to keep track of everything is a real speed boost.
There are some pretty awesome options in Darktable and RawTherapee but it takes longer to get to the same place as Lightroom and neither tool offered the same ease of noise control.
GIMP on the other hand isn't Photoshop, doesn't aspire to be and is no substitute for the full power Photoshop gives you. It's just got non-destructive layers in the latest release hasn't it? Maybe it'll start to be a bit more of a contender if that's in place now.
I wish Adobe would just bite the bullet and release on Linux, there are tens of thousands of votes/comments for it on the various forum and feedback sites calling for it stretching back probably 10 years.
If you'd kept going, speed was only his (comparatively minor) opening bullet-point. Most of his comment discussed quality issues.
That's sort of the story of desktop Linux, to be honest.
And Ubuntu was keytracking in searches, collects data on its users usage, and does centralized update authority as well. It's marginally better for a substantially inferior experience with much worse hardware support. Especially if you're on a modern laptop.
Perhaps privacy isn't their exclusive value. I think that's also a perfectly valid argument in this discussion.
So... you're saying that there are substitutes, but that they aren't as fast, you don't want to use them and that (getting back to the discussion) you don't view the privacy concerns with commercial OSes as sufficient incentive.
If so, why not just say that and avoid all the pointless flamage.