Harley Quinn is a Suicide Squad member. It's unfair to complain that they're making it Batman just because it has them. I don't particularly recall SS being a Batman group. It has Captain Boomarang in it and I don't think people think of it as a Flash group.
I don't think anyone would have minded in the first place had they not used so many Batman tropes already. As a result, anything Batman-related they bring up now only adds fuel fo the fire.