I do understand where this post is coming from. The question is basically : "Should we keep people who maybe having toxic/ detrimental behavior if they are very resourceful to the site?"
What do I mean by toxic/detrimental behavior?
- Answering low effort questions/ not closing dupes
- Being toxic to other members of the community causing mental stress
- Asking many low effort questions
The above points are not exhaustive, just an attempt to capture most of the reasons.
Different aspects of the issue
The issue, I think, is rooted in the fact that there are many ways to give and take value on MSE. Due to this, we may be wanting to 'forgive' a person giving more value in one department while they may not be in another.
Some thoughts were put into trying to solve this issue by making chat bans disconnected from site bans, and also making ban on one SE site disjoint from one on another (for lesser issues). I think these can't really tackle the problem holistically. I also think the punishment periods are a bit too high at times (stretching beyond 3 months and so), but that is different topic to talk about.
One must also account that the people in charge of who gets banned and not are also humans and they have finite time to moderate and pass judgement on the users of MSE. Hence, we can't expect them to sit down and take do a extremally deep analysis of each case before passing judgement.
Remark on the question
I think there is also an underlying philosophy in this question of 'veterans/ elderly' being given benefit. That is the long time contributor should be given more room for their behaviors because of the time period of their commitment to this site.
In real life, in most culture, the philosophy said above is applied by default(i.e: veteran benefits), but I am not sure whether a system will really benefit from people who 'can't' keep up with the change.
In my opinion, MSE is like a big machine with each member in the community as nodes, with debate and arguments between community members, the opinion of the collective changes and what is considered 'correct' also changes. Eg: the recent shift in policy on PSQs.
Now, should we focus our mental energy and resources in trying to make this system run ideally or should we focus it on 'veteran benefits'? I think the first way is the way to go, as whatever changes we've made as a community, was done only after many debates and write ups by different members in it; The ideas in the change were established to be for the better of the community as a whole.