Background checks are thorough, since 1998 over 800,000 people with felonies with sentences over 1 year and misdemeanors with sentences over 2 years have failed to purchase due to the background checks.
But they're felons, they don't abide by the law hence why
over 60% of guns used in crimes are procured illegally leaving only 10% purchased legally and .8% being purchased from gun shows (the rest being private transfers, which could have oversight). Of course passing more laws will stop the law breakers from breaking more laws.
Or perhaps it targets the wrong populace and reduces the normal everyday person's ability to protect home and household.
Also gun control is racist as fuck.