Here's a few reasons:
1. The bill develops a statewide gun registry and the local police are required to check periodically to make sure you are still eligible to own the firearm. If not, they are mandated to come knocking and confiscate it.
2. The bill requires training which is poorly thought out or defined as well as several new taxes.
3. The bill prevents people like 20 year old single moms from obtaining effective self defense firearms.
4. The bill requires you to have those firearms locked and not readily accessible anytime they are in your home, effectively preventing you from using them in the case of a break-in or similar crime.
5. The bill defines any semi-auto as an assault weapon, as mentioned this includes .22's, waterfowl and deer shotguns and many other firearms that make absolutely no sense.
6. The bill requires you to report any theft within 5 days or you are a felon, lose your rights to own weapons and can go to jail. This also opens a wide door for civil litigation that could cost you 6 or 7 figures in the event someone breaks into your house, steals your gun and then commits a crime with it. I'm not sure what happens if you don't notice the theft for five days or are on vacation, etc.
7. This is undoubtedly the first pass, future initiatives will certainly build on this. The state will have a record of every semi-auto you purchase and this could lead to confiscations in the future or additional requirements for ownership, taxes, licenses, etc.
8. Several law enforcement organizations are opposed.
9. It is funded by billionaire out of state money like Bloomberg who has publicly supported confiscation and bans, do we think he'll stop at this?