It's not a problem, neither here and, I'd argue nor on any other platform.
But according to Adelman, GoG, for whatever reason, initially pushed for Galaxy integration, assuming(?) that Axiom Verge without achievements wouldn't sell(?).
It's all documented in the thread linked by @ChrisGriffin a few posts earlier.

Which thread was that in?

In the thread below he just doubles down making excuses for his behavior repeating that it was "5 years ago" etc. He didn't even reply after Barry chimed in.

https://www.gog.com/forum/general/a_while_ago_i_wrote_to_dan_adelman_axiom_verge_and_asked_why_he_didnt_release_it_gog/page1

Regardless, Barry himself said that he didn't care and just wants them to finally release the game on GOG, yet it's still not here.

You'd think that bringing it to GOG would be an asset in the long run, but he (Dan) made it pretty clear that they don't think it's worth the time/money that would be involved.

Yes, and it's just weird considered how many games are accepted here without achievements. Why would GOG only require them for one game and not others? Matbe it was an experiment to taste the waters with developers and then gave up?

Another older one prior to the most recent one, dating back to 2018/2019, or even further?
If memory serves right...

Could try your luck direct-messaging him through here, but Twatter is likely the better option.

I don't use "social" media so no luck I guess.

I believe it's linked to in the thread that ChrisGriffin linked to.

twitter is garbage and should be banned