The activist, who had been arrested several times towards the end of last year, fled to Malaysia as she felt unsafe after taking part in a symbolic act against the monarchy.
Apart from presidential candidate Senator Kamala Harris, another Democratic candidate, Senator Elizabeth Warren had also stressed upon the possibility of breaking up Facebook.
Supreme Court elicits the central government's views on a petition seeking guidelines for regulating the streaming content that is becoming increasingly popular.
Williamson's remark on Saturday comes as May is hoping to reach a cross-party consensus on her withdrawal agreement after failing to get it through Parliament three times.
After setting out from Havana's Paseo del Prado, one of the city's main boulevards, the marchers came up against a large number of police and state security forces.