They were elected with that mandateArchived Message
Posted by Matt on March 28, 2019, 10:17 am, in reply to "Re: No e (loud)"
I've no idea how Sinn Fein supporters feel about abstentionism in the face of Brexit; however, I doubt the party will alter its stance on a whim without debate and consultation with members/voters. Their MPs were elected in 2017 on an abstentionist mandate.
I'd suggest that continuing their rejection of British claims of sovereignty over Ireland by abstaining from UK parliament is much more important to them and the majority of their supporters than Brexit. One issue is relatively peripheral and fleeting, the other is core and permanent.