This is something that can be proved to be true or not and hopefully will do in a court of law.
Somebody saying they felt suicidal can not be proved either way, therefore you apply sympathy to the situation and don’t call that person a liar infront of millions of people.
Bit of a daft comparison.
You can question the motive.
Andrew has a criminal motive to his excuses. Meghan has financial and reputational motives.
They are similar in that regard. They are also both high profile royals undertaking a high profile, entirely optional interview.
Ask yourself why they wanted to do it. Not agreed to it; wanted to. Then perhaps you'll understand why it's valid to doubt them both.