If the protest being held during an open day was intended to put off prospective students, does that mean the protesters are aiming to bankrupt the university? Or that they don't care about any financial damage? Or that they don't mind if their own education is affected?
It seems really counterintuitive to protest to prospective students and their parents rather than focusing on the administration. Is it some kind of brinkmanship? "Sack her or we will keep losing you money"?
Is the university even in a position to sack her? She has broken no laws, she is covered by employment law even if her ex-union is hostile, and the potential financial loss to the university might be higher in sacking her than it would be in ignoring these protests.
Strikes me that these protesters are performative, and that this masked nonsense is more about maintaining social status in their peer group than anything else.