There's some strangeness in the way these games are presented. Having recently picked up Shadowrun Returns in the giveaway, I expected to run it on Windows since only Windows and Linux are listed on the store page. Oddly, the Mac version was still available for download once I had the game, so I gave it a try. There's no notice about it being 32-bit, which meant my attempt to install it was wasted time.

So it seems that for some of them, they won't even inform you that the 32-bit version exists but make it available for download. Granted at this point most people have updated to a system that doesn't support 32-bit, so maybe it makes sense to drop it as compatible, but the downloads should also be dropped or at least flagged.

I think it makes sense to leave them as they are for those few with older systems. It also makes sense not to advertise Mac installers which are not working on modern systems anymore and therefore are not supported by GOG themselves (which is caused by Apple's choice and therefore their fault by the way).

But I agree it would be nice if they mentioned somewhere they provide bonus 32-bit installers and that they should be labeled as such.
(There's a notice under system requirements on the game page saying "The game is 32-bit only and will not work on macOS 10.15 and up." but I suspect that's a remnant from the transition period, while they were still supported)