1. It comes nowhere close to what a dishonorable discharge is typically used for (murder, sexual assault, desertion, etc).
2. Most of these Reservists and Guard members are probably not on active orders at the moment, therefore they cant be discharged because they arent in an active status to be discharged from.
3. They arent going to bring thousands of reserve members onto active duty for the sole purpose of disciplining them, it would cost tens of millions in travel, lodging, per diem, pay and benefits not to mention the administrative man hours the commands and justice system would have to expend.
4. They basically arent meeting their medical readiness requirements, as reservists we had these for lots of things, annual dental exam, tetanus shot every 10 years, HIV test every two years, etc. There are two realistic paths this could go, they are either administratively separated if they dont meet readiness within a given timeframe (which is basically just some paperwork and is non-punitive) or they are placed in the IRR (Inactive reserve) until their current enlistment expires. There are some other administrative mechanisms for specific scenarios as well, but they arent punitive either.
5. They could recoup prorated portions of any bonuses given but this is generally not going to be too much for reservists. Like if someone got a $10,000 for a specific MOS for 4 years obligated service, they only give half up front then spread the rest out over the remaining years. So depending on the timing they might not have to give much back unless they had just recently received the first half.