Teresa May's moral cowardice noted!
I actually agree with the UK's decision not to intervene (though not with the Bermudan legislature's decision). It would undermine the principle of domestic self-governance that the UK extends to its overseas possessions for the UK Parliament to overrule the local government.
There are cases where I think the intervention would be appropriate (for instance, if Bermuda moved to criminalize gay sex again--it was legalized in 1994, but the age of consent for male homosexual relationships is higher than that for heterosexual relationships or female homosexual relationships; as near as I can tell lesbian sex was never illegal, because of course), but this isn't one of them.