What is the purpose of free software if you are not supposed to use your freedom?
The purpose of free software in regards to what the OP speaks of is freedom from Google and code/hardware control of his e-mail servers. That said, nobody sane said that free software is automatically and guaranteed to be easier, better, or even cheaper than proprietary software (cheaper as in opportunity cost, not necessarily as in price).
I wouldn't say anyone is seriously telling him he's not supposed to use his freedom, but that his freedom comes at a large time cost. Is being free from Google in regards to e-mail worth it based on an ideological stance alone? That depends on how much you value your time in relation to how much you value your ideological stance. Seemingly, in regards to e-mail servers, people value their time over their ideology.