Yes I'm aware of the security tradeoffs with testing, which is why I've started refraining from mentioning it as an option as pedants like to pop out of the woodwork and mention this exact issue every damn time.

Also, testing absolutely gets "security support", the issue is that security fixes don't land in testing immediately and so there can be some delay. As per the FAQ:

Security for testing benefits from the security efforts of the entire project for unstable. However, there is a minimum two-day migration delay, and sometimes security fixes can be held up by transitions. The Security Team helps to move along those transitions holding back important security uploads, but this is not always possible and delays may occur.