If this was an open source "project", rather than a "foundation" whose mission is to build a better web for its users, I'd say it was their call and that's the beauty of OSS. This is not that.

This is another decision in a long string of decisions which are either not in their users' interest, questionable, or poorly communicated and implemented.

If I were to give the benefit of the doubt here over the question of whose interest this is in (Mozilla or its users) it is still being horribly communicated (otherwise one might better understand why it's in one's interest) and horribly implemented, to the point which I'm beginning to question whether Mozilla, as an organization, is up to the task of building a better web for its users.

Why not more discussion around Pocket, the new tab page, Thunderbird support, etc. Why pop these decisions, fully made, on their user base? And why not, in the case of XUL, incrementally replace features or develop in parallel until a drop-in, validated solution exists.

To me, one of two things is going on. Either Mozilla is not acting in the best interest of its users or this is amateur hour. Both scenarios suck.