yes but that is a petty point.
I mean you can also cannot tell if the chess grandmaster is 2100 after two years or whatever arbitrary penalty that you assign. He may be 1900, or 3875 for all we know. Only playing will tell.
Simply because the elo strength is not absolute but relative to the active playerbase. I thought you got this point already but it doesn't seem so.
Indeed in chess one can start playing again but there is no penalty. Only the last score is registered and that's it. If one is not anymore good the new games will show it letting him losing points pretty quickly, if not, he gets removed and that's it.
Collecting best scores is just fun but nothing else, already scores made with different k factor values (so from a league to another) are incomparable.
So the point is to take those inactive (for the ranked games) players away from the screen, not being petty willing that the scores have to be penalized arbitrarily.
Also it should be obvious that since the amount of players that go inactive are way more that the amounts of players that stay active, with negative penalties the system regress more and more. It is nothing difficult to see, a bit of observation, common sense, a bit of time to plug numbers if one does not want to make a program and math concepts of middle school at best (sure, one has to consider the actual context as well, like elo formula and matchmaking, but that is granted).
Now since experience says that it is likely that you will clinch on your point, feel free to do it, but I explained even too much for someone that should have already noted it.
For me it is obvious that penalties are counterproductive and here something simpler is needed, for your is not, that's it.
Also would be interesting that you provide sources (no "google it" is no source. Nice try) for your claim, even just to see another perspective. Could you link 2-3 (only one is too little) official pages where the staff of the online game explains the penalty points if one goes inactive? Of course should be an active rule, not something that was changed due to the community complaining.