In Thailand it now seems that any opposition to the monarchy is unacceptable.
That country’s electoral commission has petitioned the constitutional court asking that it shut down the Thai Save the Nation party on the grounds that it is “hostile to the constitutional monarchy”.
This followed the party’s nomination for prime minister of the sister of the king. That nomination was blocked by the king.
In Thailand for a long time citizens have been imprisoned on a charge of lèse-majesté, that is for insulting the king. Now it may be that just support for democratic institutions as opposed to feudal ones is against the law.
In the United Kingdom it is not illegal to oppose the monarchy. However, those who do not have an allegiance to the Windsor family are banned from parliament and from many public offices.