Sentry is unfortunately not Free Software/Open Source

Promoting and building infrastructure for the support of FOSS is not "morally grandstanding", it's acknowledging that we're all standing on the shoulders of all those guys+gals in Nebraska+elsewhere.

If you don't like people being able to take their code out of FOSS, well then don't contribute to MIT-licensed stuff and don't sign any CLA. Fine.

Re-licensing some is not morally or otherwise objectionable if the license allows it. The code (as of before the license change) is still free and can be forked easily. This is the real world, not some FSF utopia which considers non-libre source to be morally objectionable *in itself*.

If you want "objectionable", then let's talk about all the closed-source Linux device drivers and the locked-up devices and whatnot out there. These *do* prevent you from exercising your free-source rights.