I do kind of agree with the sentiment of this, because there's a lot of 2.0 add ons that don't work or need updating to 2.1. And some devs are now releasing two version of their add ons, one for 2.0 and one for 2.1, which can get a bit confusing.
For example with Xon's Content ratings, there was a period of time where people were trying to install the 2.0 version on 2.1 and it was causing issues because it hadn't been updated yet, but people were downloading and installing it anyway.
Then you have devs like Jaxel who are releasing two version of their add ons, one for 2.0 and one for 2.1 which gets confusing. Is it possible and best practice to have both version rolled into one?
Then it seems that some devs say you should to upgrade your add on before you upgrade XF, and I think some say you should do it the other way around. There's does seem to be a bit of inconsistency in the handling of the transition from 2.0 to 2.1 across the board.
I do get that you don't really want duplicates of the same add on in two different categories and two support threads though if you can help it.