Ok here's the breakdown of how I feel, as well as what actually has happened and the factors behind why this happened, and why this isn't just a regular case of someone leaving a healthy player on IL, and the way in that it is most likely to happen again.
Not gonna lie it feels like I'd be getting punished for having both a good draft (because all the guys I drafted actually have some value) and also finding good waiver pickups. I can no longer make FA adds (idk if I can trade or not) and I missed out on adding Deni Avdija (for a 3rd time this year

) because of that.
Again it has to be stated that it feels like such a rare scenario that requires basically every single player on your team to be rosterable. Normally when this happens it's to a team's detriment. But in this case they're all about equally producing AND my entire roster is playable. I've never even seen this happen before in our dynasty league.
Having healthy players on IL has never been called out before because again, previously it's always been a detriment to do this. So for it to be called out now for the first time when it has an advantage is just a bit annoying. So it seems right now it qualifies as "abuse" once it meets these conditions:
-your replacement player is as good as the IL player
-your roster is completely full of players that should be rostered
So I don't feel like it actually even qualifies as "abuse". I'm just doing what the rules allow me to do because of how much talent I have on my team. I don't think there's another team in the league that can conceivably pull this off.
THAT BEING SAID
I can understand how it could be exploited by rebuilding teams to stockpile young players with low value. Because the definition of "rosterable" changes when we talk about rebuilding teams, and prospect level players can have apparently such low or "unknown" value (in this sense, they are "rosterable" because rebuilding teams need prospects) that it can potentially be easy to see a rebuilding team with a roster full of ~20 year old prospects with unknown values. So once a prospect with "unknown" value gets an INJ/O/GTD tag they can just put him on IL and find another player from the FA pool. If the added player is a prospect (again, value unknown) then he in effect has the same value as the IL player, and if the added player has value from actually producing stats, then there is no reason to remove the healthy player from IL.
^This is ostensibly speaking the same as what I have been able to do, but in the above example the prospect players are not worth as much as, say, Okongwu and Vanderbilt. So the above scenario is hypothetically more common than my personal case.
I'm willing to vote on something like this. If we do vote for policing the IL slots we'll have to come up with some regulations, and all managers will have to be aware. And then we have to decide whether to implement it now or in the offseason.