After you buy your hardware it's yours to do with as you will. If these hacks result in the ability to load whatever you like on the T2 and intel proper then why not? Hackers like to hack. A lot of programmers are also hackers (in the traditional sense, not the negative sentiments that the press gives it)

Then perhaps they should sell it, and stop ignoring people who want it?

Benign neglect (not creating limitations) is not the same as active interference (actively preventing) and Apple is much more on the side of active interference. They could simply do nothing (which is cheaper). They choose not to, at which point we get to question their motives.

In the end your question reduces to "why do you want anything at all that someone doesn't already make?" and that doesn't make alot of sense given that new products come out on the market all the time.

Why would I not? Why should I accept everything companies do without ever complaining? Am I not allowed to tell the fishmonger that his fish doesn’t look that fresh to me? In the same way, I’m free to tell Apple their fish would taste better with some adjustments.

Because a hardware vendor telling you what you can and can't do with the stuff you own is immoral.