Welcome!! I think I know the site you went to and you are right, the atmosphere is very negative there.
That being said, I think you may have difficulty executing your plan. I don't know if you plan to work at home for a local doctor or practice (which is very rare these days to get a position like that), but if you want to work for a transcription service (and most of them are very big--they have gradually bought out the smaller services), you will have a very difficult time finding part time work. The overwhelming majority want full time, and most of the positions are 2nd and 3rd shifts and/or weekends. Working part time at first, it would take you awhile to get up to speed, and there are production quotas required by these services and they are increasing all the time. If they have part time, they would require that you transcribe 5000 lines in every 2 weeks.
Another point--these services want people with 2 years of experience minimum--there are exceptions but those don't pay as well and you should be fairly compensated for what you are required to learn in this profession. So you have the Catch-22--you can't get experience because they won't hire anyone without experience.
There is a difference in schools, too--you will learn a lot, no doubt, regardless of which school you choose, but it might not be all that you need to know to be able to be successful.
I would recommend calling MT companies and asking them if they would hire a graduate from X school. Some of them tell you right on their websites which schools they recommend. Also, make sure you go to an AHDI-approved schools. These schools have met the minimum standards, so at least you have some assurance that you are on the right track. You can find a list of their approved schools at www.ahdionline.org.
Hope this helps--not trying to discourage you, just make you aware of the pitfalls. Those negative MTs are over the top. There is a grain of truth to what they are saying, though, but their delivery lacks a lot to be desired.