Marxists, or at least Orthodox Marxist-Leninists, don't believe in free speech or at least the iteration spelled out in most, Western liberal democracies. I'm not condemning him for saying he shouldn't have a right to his own opinion, but free speech also allows me to criticize his, too. Its a two-way street. I can criticize him as much as he feels the need to lay out his grievances online on Twitter. Too bad in places like Venezuela the country's president, Maduro, has his party's followers attack counter-demonatrators, opposition politicians, activists, some left-leaning on the streets in violent demonstrations about why a once-prosperous, oil-rich country is now considered South America's Zimbabwe. Even Chile's center-left new President criticized Chavez's and Maduro's authoritian crackdown and repression and called out other leftists, liberals for their past hesistancy in doing so with other regimes. Frankly, from an historical perspective, no true Marxist state or socialist/communist state has ever existed where free speech or a free press was ever openly, fully allowed or permitted and the only voices allowed were state-sponsored media mouthpieces. There's also never been a true Marxist state, and likely they'll never will be, but don't think that won't get in the way of anybody trying.
Actually, some British Royal historians, like Kate Williams, have said or spoken out about how Queen Elizabeth's death will or might lead to significant political changes in terms of Commonwealth countries like Australia, Belize, Jamaica, Barbados might become republics and the Scottish independence question was raised, albeit briefly. It wouldn't surprise me if Welsh independence didn't become a issue like their Scottish predecessors did or have over time. In fact, if we're being realistic, it wouldn't surprise me if Australia didn't declare itself a republic within the next 10-15 years. Jamaica and Belize, too probably.