He's a colossal cunt as well as an untrustworthy slimebag as well as his newspaper editorship career goes (anyone remembers the staged images of British soldiers in the Mirror pissing on prisoners?). Not to mention the whole City Slickers corruption/ insider trading scandal, which he was at the centre of but somehow escaped unscathed.
Ultimately it comes down to his phsychotic-level egotism, which is where his vitriolic hatred of Meghan and Harry actually comes from. He was snubbed for a social event Harry and Meg were throwing, and the rest is history.
Harry might be a privileged twat, but not more so than any of his relatives, and no matter how much one might despise him in general, everyone should be on his side regardinig his (and other celebs') fight against the abominable tabloid British press. Because any victory against the nefarious practices employed the and relentless bullying dished out by the gutter press is undoubtedly a Good Thing regardless of who the other party is.