those are likely most of the same reasons these apps are not sandboxed (switching "not my project" with "I'm not payed work on this").

Those are valid reasons not to improve a project, but it doesn't make your project immune to criticism. If you're not going to take the time to make your project better, that's fine, but other people are still free to point out that your project isn't very good or that your project could be much better if you managed your time differently.

Tepix's point was about entitlement, not criticism.

"There is no excuse for ___" definitely crosses the line from criticism to entitlement. :^)

So open source always gets a free pass? "You should be doing X as what you're doing represents a security threat." "Well, submit a patch then neener neener."

C'mon.

they don't, it's just that the statement "there is no reason for this software not to have a sandbox" is wrong, because, well, there are many reasons.

A correct statement might have been "there is no technical reason that prevents sandboxing, given a ton of work".