> None of this is user-friendly - all of it is obfuscated
This is a message which is printed with very clear instructions the first time you run any command. It’s a simple command and there’s no noticeable difference in resource usage compared to the actual package management system, which also needs environmental variables to be set.
The big thing you’re missing is that the Homebrew maintainers are freely giving you the product of many thousands of hours of skilled work, the kind of service developers used to pay money for. In exchange, they ask for some non-personal statistics to help them avoid mistakes which could cause problems for you. I don’t think it’s fair to act like they’re tricking you when you’re getting so much out of the deal and it’s all disclosed publicly. They could be tracking stats on the package distribution infrastructure without your knowledge at all but instead chose to be fully above board about what the system does and why, and offer a trivial opt-out mechanism.