No one is arguing that Meghan Markle has been treated poorly by several media outlets. Following her and Prince Harry's announcement that they were "stepping back" as senior royals, which was then followed by a meeting with the Queen about what that actually meant, Buzzfeed published a side-by-side headlines comparison of Meghan vs. Kate Middleton. Of course the former's were scathing and the latter's were glowing.
While I won't defend the outlets that criticized Meghan, the Duchess of Cambridge received the same kind of treatment when she dated William. At that time she had no legal counsel, no security and no press team to make a statement on her behalf, since she was only the girlfriend of a prince. All she could do was keep quiet and smile. And that's pretty much what she did.