Neither do I, and on rereading it's not as clear. I want there to be an option to set a primary keyword, for pretty much exactly the reason you give--I have some icons with shared usage, which I plan at some point to split, but others are shared usage that I'm unlikely to want to split.

So not enforced, not overriding current behaviour, but supplementing, to allow those of us with old keywords to keep them, but not have the clutter they create.