That restriction makes the license not Open Source. Open Source licenses MUST allow anyone to run the software, for any reason, by definition. Even "as-a-Service". It's a perfectly fine restriction to have, but it shouldn't be called an Open Source license.
(Timescale engineer here)
While AGPL is a value-add for many, TSL isn't as ambiguous in some regards and provides a lot of nice "we won't sue you for this" clauses for users. Clear communication regarding its FOSS status will only help!
That's why Open Source came up in the first place - pointing out that one of the basic reasons for the Timescale license to exist in the first place is to restrict one of the major reasons Open Source licenses exist.
There were also no claims about whatever definition of restrictive you were using. It was just a short statement that the Timescale license was designed to be less restrictive than the AGPL. You can't really be that surprised when somebody comes along and starts judging it by Open Source standards after that, can you?
Comparisons to Open Source and discussions of the pros and cons of both approaches are, of course, fair.
I think Timescale employees should remember to preface "This is our belief on the definition of restrictive" when describing the license as more open than open source licenses, given much of the community might disagree (sometimes vehemently) about that take.