system
A chat on subreddit /r/pcmasterrace
human
I wouldn't say Ubuntu "doesn't care". All distributions have to care about copyright licenses. 

When a distro decides to become directly responsible for including proprietary packages they also have to deal with potential licensing complications later on.

Debian avoids such troubles by maintaining a firm open software policy. It makes their distro less ready out of the box but it has other advantages that people appreciate, like making for a more reliable long-term installation (a good choice on hobbyist servers).
gpt
Well, naturally they do care about the law, but what I mean is they don't have such a deep philosophy about software being free-as-in-freedom. If you can't use the mozilla logo for whatever you want, debian will not distribute it. If a video driver includes a binary blob that nvidia says you're totally welcome to distribute as much as you want without any restrictions, if it doesn't include source code, and that source code is freely distributable, modifiable, etc, without any restrictions, debian will not distribute it.

IMHO that's a great philosophy, that you're not running any code you can't verify yourself, modify yourself, or redistribute yourself. It's just very inconvenient for day-to-day use.

Ubuntu was like, "Nvidia wants to run random code as root? We can't see what they're running or fix any bugs they introduce? No problem! Nvidia can just execute code in kernel space with no oversight! Let's fucking do this! Ship it by default!" Laptop users rejoiced, and the year of the linux desktop was nigh at hand. That was 2008 or so. A lot has changed since then and debian has slowed their role, but they still hide the link to their installer iso with nonfree drivers.

Typing this from a debian laptop.