It won't be homophobic at all, it might be something that targets blue collar voters especially. Those voters might not want to vote for a lesbian, so might go to the NDP for economic reasons. The NDP doesn't have to do anything remotely resembling anything homophobic, they just have to target the demographic.
It makes me feel icky thinking about it, but it might be a successful strategy. The latte liberals (the "Jack Layton Liberals/McGuinty New Democrats") in Toronto are going to be more likely to stick with the Liberals now.
But who knows, as I've pointed out, Wynne got a lot of rural support in her candidacy.
Any party who brings it up will pay dearly for it, but at the same time it could work in favour for both the NDP and PCs. I doubt it will make much difference amongst blue collar workers. Rather I think the South Asian community who tend to be left leaning on economic issues as well as the Muslim coummunity are groups who I could see going NDP over this as many are left wing economically but socially right wing. As for the blue collar, that will largely be an NDP/PC battle although considering a high number are white males over 50, this group might vote PC in greater numbers than the province as a whole. In many ways your wealthy university types I think are more likely to go NDP as despite their wealth, they tend to be quite progressive on most issues.