Go ahead. Bash away. It's not forbidden to criticize these people - we live in a country masquerading as democratic after all - which is why the effort to close down debate by people who support this institution is less than surprising, coming from those who oppose a view for their own Head of State.
The Windsors are UK national and international diplomats yet not one citizen of these islands has ever voted for them.
They are supported, in terms of large security costs and the expensive maintenance of their huge portfolio of grace-and-favour homes, by the UK public/electorate, who don't have recourse to a vote if they don't feel their performance is up to par.
It's not only the Head of State who receives these privileges but the whole of her huge, extended, bloated family (her cousin lived in Kensington Palace for years practically rent-free).
Nobody knows what they pay in (voluntary) taxation - paid at a rate they think they will, and purely because of public disapproval at the time. That's because the establishment doesn't want you to know. The Windsors are the only people in this country who are exempt from the Freedom of Information act.
Dubious stories about their doings are quickly rugswept and conveniently disappear from a media over which they hold far too much control (cf. certain proclivities of the Queen's second son).
They profess to hold no power. Yet the unelected Head of State holds regular meetings with the elected Prime Minster, the contents of which you are not allowed to know.
They're extremely powerful. They're very censorious. They're nepotistic. They're undemocratic and anti-meritocratic. Their cost is only one - and not the most important - problem with the very existence of these people in the positions they hold.
Bash away, OP. Bash away.