If you want to you could ask the OP of the post since they’ve taken into account of asking for ID verification (your Battlenet code) to verify your vote and answer.
It would be bias if they mainly just asked only Mercy mains, but they managed to even sub categorized non-support and non-Mercy players what they think as well, so theres not much double standard since its showing what both sides think about Mercy’s balance rn.
And they did give a disclaimer that it does not reflect the entire playerbase since, not a lot of people go on the forums, but it still does relfect peoples opinion about her balance rn. Check out the post, I dont wanna copy paste the whole disclaimer since its really long.