It's using their British titles as a platform
But they aren't using their titles, organisations and publications (like Time) that have worked with them have stated this. They are well known even to go by Harry and Meghan and this is exactly what they are doing.
I know they haven't given up their titles, but they shouldn't feel they should have to, especially to placate those who will most likely never be satisfied anyway.
None of this is disgraceful:
《Harry and Meghan called on viewers around the world to act with compassion in both the physical and digital worlds, use their voices, be engaged within their communities and the civic process, and care for one another, according to their representatives.》
《"When one person buys into negativity online, the effects are felt exponentially. It's time to not only reflect, but act," said Harry in his video remarks.》
《"As we approach this November, it's vital that we reject hate speech, misinformation, and online negativity. What we consume, what we are exposed to, and what we engage with online, has a real effect on all of us," he said.》
《"When we vote our values are put into action, and our voices are heard." Said Meghan》