There has been definitely been a strong a push, but there's also the benefit of time - the public is used to her, so whether they like her or not there's not an active push from them to remove her. At a certain point, even the most avid and obsessive royal fans had to realise they don't actually own the royals as people, so can't control their choice of partner.
In trying to paint Camilla as dangerous, Harry is making a very personal and emotional attack - he can see her as the villain so he can avoid acknowledging his father's adultery, he can see her as the villain to avoid acknowledging his parent's toxic marriage. But he can't make that fact or sell that emotional attack easily, as it only works for those also emotionally invested in the same way.
He also runs the risk of inviting direct comparison to the PR and press onslaught of himself and his wife - it's hard to call out the active media push to rehab Camilla's image without risking comparison to his push to rehab Meghan's after the press turned on her. Why is one dangerous, but the other necessary?