They might have set up the user agreement for it. Stackexchange did and their whole business model was about catching businesses where some worker copy/pasted code from a stackexchange answer and getting a settlement out of it.
I agree with you in principle (hell, I’d even take it further and think only trademarks should be protected, other than maybe a short period for copyright and patent protection, like a few years), but the legal system might disagree.
Edit: I’d also make trademarks non-transferrable and apply to individuals rather than corporations, so they can go back to representing quality rather than business decisions. Especially when some new entity that never had any relation to the original trademark user just throws some money at them or their estate to buy the trust associated with the trademark.
An alternative that will avoid the user agent trick is to curl | cat, which just prints the result of the first command to the console. curl >> filename.sh will write it to a script file that you can review and then mark executable and run if you deem it safe, which is safer than doing a curl | cat followed by a curl | bash (because it’s still possible for the 2nd curl to return a different set of commands).
You can control the user agent with curl and spoof a browser’s user agent for one fetch, then a second fetch using the normal curl user agent and compare the results to detect malicious urls in an automated way.
A command line analyzer tool would be nice for people who aren’t as familiar with the commands (and to defeat obfuscation) and arguments, though I believe the problem is NP, so it won’t likely ever be completely foolproof. Though maybe it can be if it is run in a sandbox to see what it does instead of just analyzed.