Ok, skimmed through the article.
The problem is the phrasing:
"This bill prohibits a person, with certain exceptions such as for law enforcement, from selling, transporting, manufacturing, or possessing any hollowpoint bullet, any bullet that expands or flattens easily in the human body, or any bullet with a hard envelope that does not entirely cover the core of the bullet."
This description bans more than just hollowpoints.
EDUCATION AHOY! (This will be long.)
There are several types of bullets used in rifles and pistols.
From the beginning of firearms we get the simple lead bullets, a lump of lead which hits the target and does the damage with its weight but it is not very tough material so armour and such will stop it and its behaviour in flesh is unpredictable.
Then we began covering the lead in a metal covering or a "jacket," making the full metal jacket (FMJ) bullets. This is an improvement in many ways, the bullet behaves better inside the barrel making it more accurate and allowing more powerful charges. I also means that when it hits a soft target it stays in the same shape. Geneva convention and such demand that all bullets used in war are like this because a simple clean hole through your body and organs is seen as less barbaric than a bullet that rips you apart (coming in the next section.) Unfortunately this does mean a small wound canal. Unless of course you do what several armies (USA and Russia for example) do. You put the weight of the bullet to the back of it causing it to "tumble" or spin
inside the body. This causes a huge wound inside the body making it more lethal.
Next we get the hollowpoint. Since the tip of the bullet is open once it hits a target, for example a deer, the tip of the bullet start to open up. The bullet expands and therefore it creates a bigger wound channel or hole. This means more damage to the flesh, more likely to damage something vital and it also makes the bullet use up its energy faster making it less likely to go completely through the deer. This might sound barbaric but it is more likely to give a quick death, which in my opinion is more "humane." To be hones I don't know any hunters that would use hollow-points. They usually expand
too much and damage too much flesh making it inedible. These are the wants the lawmakers want to ban, unfortunately the law would also ban...
Semijacketed bullets. These are basically a hollowpoint bullet with a lead or plastic tip inserted into the hole. By having a softer tip we achieve a mix of the previous two bullets. Since the bullet is shaped more like the FMJ which has better aerodynamics than hollow-point but since the tip is softer it will be pushed in and the bullet start to expand just like a hollowpoint. With current technology the amount of expansion in the bullet can be controlled very well. In fact, I'm not sure if hollow-points have any real advantage over semi-jacketed bullets anymore.
I think the semi-jacketed are the most commonly used rifle bullets in Finland. In fact the laws usually demand that they are used for several game animals. (You can hunt birds with FMJ in Finland but that's about it.) And according to Politifact Wisconsin has similar laws so this would indeed prevent deer hunting with rifles.
TL DR;
Law would ban all expanding bullets (including but not limited to hollow-points). Wisconsin law says that only expanding bullets can be used in deer hunting, this limitation has valid reasons. Therefore: This new law, if passed, would stop deer hunting with rifles. Bows and such might still be allowed.
Also, before expanding bullets were invented rifles, muskets, flintlocks etc. had simple lead bullets. Those work but the newer types are more accurate, create better and more controlled wounds and can be more powerful.