Death Battle, as in Chad and Ben, don't hate Dragon Ball and it's silly that this is still a discussion. They clearly love it, they've stated they like Goku more than Superman, and are more than likely aware of Dragon Ball's role in revolutionizing modern battle boarding/power scaling as well as how it helped put Death Battle on the map way back when.
Shit, I don't even think they research team hates the series in of itself, I think a very select few just aren't good at researching it and can be overly dismissive, defensive, and antagonistic towards Dragon Ball fans due to the backlash they get when they shit the bed, whether it's speedy and the sun disc shit, or ultraguy headcanoning god tier base forms away out of his personal dislike of multipliers, as well as finite speed Xeno Trunks, cherry picking low end Planet Vegeta destruction calcs, the list goes on.
So, at worst, like literally the very worst you can put on anyone on the Death Battle staff is a few researchers who aren't good at scaling Dragon Ball and don't particularly conduct themselves well when interacting with the fandom or responding to feedback or taking accountability for fck ups. And like if I had to reach for something, iirc one of the current discord moderators had a history of very generally accusing Dragon Ball fans of horrid shit and would instigate shit in their discord topic and turn around and play coy.
Again, this is me actively searching for this apparently institutional mandate from Death Battle Inc that had declared it a core prerogative to hate Dragon Ball. They made a shitty episode over a decade ago, move on.
So yeah, it's nonsense and it makes me roll my eyes when I hear it because there are valid critiques to make but this is not it.