A primary, fundamentally, is nothing more than a race for a party endorsement. This is why primaries should be closed, internal, party procedures and definitely not state-funded. That said, there is no legitimate cause for banning any person from running in an election simply because they failed to be endorsed by the party. There should be multiple "Republicans" and "Democrats" on ballot if people want to run and declare themselves as such. That's the difference between ideological statement by party affiliation and outright party endorsements.
This Bill is a disgrace and so is his proposed policy.