Half is close to my 45%, so I agree.
I'd say half of that 45% are not "bad" intentionally. There is the huge half of DMs that are just bad through inexperience, misjudgements and not thinking things through.
And most of the rest.....well, power does corrupt in nearly everything. This happens to people a lot....
So anything less than "average" is bad. Which is why I think the poll was meaningless.