This has been discussed ad nauseam in previous threads ...
They jumped, they weren't pushed, but what they're bitter about is that they thought Harry would be able to railroad the Queen into agreeing to what they wanted (half-in, half-out, Sussex Royal website/branding, pursuing commercial ventures while still representing HM, monetizing their royal status), but Harry failed to get that private meeting, because word got out what they were up to, the Queen was suddenly unavailable and they were thwarted by Charles, William and 'the men in grey'. They've been out to exact revenge ever since.