Unethical or not, it's clear that you have way more independence and control
over your computing running the software on your own than using a service.
And since the whole point of the free software movement is to have control
over your computing then SaaSS should be avoided. SaaSS is even worse than
off-line proprietary software in some aspects:
* If you have a computer with proprietary software that works without
Internet and you don't connect. Then you know your data is safe in terms of
privacy. With SaaSS you always have to send all the data to the server in
order to get the result, clearly not the best in terms of privacy.
* You can at least try to reverse engineer the software and change it. With
SaaSS you can't, unless the source code from the server is public. But if you
want to make changes to the software you obviously have to run it on your
computer, but then it's not SaaSS anymore.
But I don't think that SaaSS is bad always. If you only use SaaSS
sporadically for reasons like "I need to do a translation but my brother's
computer don't have GNU translator" then it's okay, because you don't depend
on SaaSS, you only used it because it was more convenient at that temporal
situation. But when you depend on SaaSS then in my opinion it can be as bad
as any addiction.