I don't agree that it's a pointless petition.
I have nothing against coalitions as such and think they are a perfectly valid way of running a democracy.
I don't expect it to result in a Labour government and I'm not even sure I would want that to happen.
But it will, I hope, send a clear message to May that it does matter who you ally yourself with, that she cannot count on the support of the electorate for pretty well anything she decides to do to maintain power, that the Good Friday agreement matters, and that misogyny, homophobia etc are valid concerns. Oh, and that we don't care for hypocrisy.