It's not the haters fault, it's the wankers.
What wankers are you talking about? pretty sure it was a good chunk of the Batman fanbase himself that didn't want him to even hurt Darkseid, and like any other character his fans WILL USE FEATS when he gets them on the battle board,it's the haters who keep dismissing everything as PIS/WIS which leads to flame wars. For example Batman kicking Superman=PIS,Batman beating Superman with a power armor that has anti Superman weapons is not PIS no matter how much Superman fans want to believe.
Batman's not underrated. He's just usually pitted against people that he can't beat, because he does it in the comics, and when you apply logic to it, Batman can't pull it off the wins unless he's given some sort of boost, like one of his Armors.
That and most people just love to post "Speed Blitz," and be done with things.
Now, put Batman against someone in his weight class like Bronze Tiger, Green Arrow, Richard Dragon, Moon Knight, Nightwing, Red Hood, Black Bat, Girder, most of The Rogues, Katana, etc. Then you have plenty of room for debate on both sides, that Batman would probably win for a fair amount of these.
Don't put him up against Hawkman, Aquaman, Entrigan, Drax, or anyone like that in a random encounter with no prep time and argue he'll win. That is how you start flame wars.
Batman would wipe the floor with Hawkman,even Aquaman is easy pickings with some prep.