I made an ADA argument to the CGF lawyers for suppressors a couple years back and was blown off and told we had other more pressing matters. Now we have the Hearing Protection Act...which got shelved.
How about the disadvantaged minorities argument? Voter ID law comparisons? $25 is too much for people to pay to get an ID to vote, places to obtain IDs are too far away, but more than twice that year after year just to keep your 20 year old AR in compliance? Ranges and gun shops are pushed further out costing you more time and gas just to get there? Even if it was only for the usage of mandatory safety classes, I don't think anyone could reasonably argue that having to drive from SF to South San Jose / Morgan Hill is not an undue / unnecessary additional burden.
So basically, they want poor people to be able to vote for them but not own weapons / exercise their 2A / defend themselves. No issues with roadblocks and additional cost burdens on firearms and ammo.