Haha me too man, me too.
(Edit: I don't mean that sarcastically, I'm genuinely interested how others would make this thing.)
But the camera itself should support MTP, USB mass storage, or something of that nature, and should just work on any platform. If it doesn't, that's a pretty silly oversight.
Is it obvious? Is it free (as in resources) to support agnostic platforms and systems? Is the threshold for making anything that it needs to be compatible with everything?
However a security camera that works with all operating systems just needs to expose a drive via USB… as has been done for decades now.
1. Not use a filesystem on the SD card;
2. Write RAW files only
This means software is needed to both transfer files, and to convert them into an image format.
Personally, I'd put that software on board, with extra dedicated hardware if necessary (it can be powered off of USB), and make the device appear as a massage storage device to a USB host.