Because they don't have a snowflake in Hell's chance of accidentally getting real power. Well & truly so having become a non-entity after their antidemocratic behaviour after the referendum. At the very worst they could end up holding the balance of power (God forbid). But vote Labour and you risk getting who you actually voted for into government, and at present, while they have no regard for the masses, which is meant to be their raison d'etre, except to monitor/control them, force unpopular woke type policies through, and try to align with the EU and all that the EU demands, well that would be a major error, and embarrassment. Think of the guilt one would feel. Until they return to their core values Labour isn't a true left of centre party, they are too preoccupied with nonsense that is detrimental to the nation.