Thread:
Britain is a Constitutional Monarchy which means they have a Head of State that is part of the legislative authority together with the House of Lords and the House of Commons. The Monarch and her Successors (people in line of the Throne) which includes Prince Harry-

are expected to be a political because if they become the Sovereign one day the government, MP etc are considered theirs. So they stand above the parties. Meghan isn't in line of Succession nor a senior member anymore who represents the British Government so in theory-

she can do whatever she want in a general election. There isn't a law that says she can't talk politics, vote, or even
be elected in an election.
And the Brits know that!!! Simply because they have no written constitution to back there ridiculous hate towards Meghan up.

It's just not done (tradition) for the Royal Family to be political.
And since they have broke tradition by actively removing Harry's military appointments and chase them both out of the country, It seems fair that the Sussexes break some non-existed laws/rules.