Oh, hell no! I really hate hearing stories about FTO's that break students and new EMT's down. The bottom line is you're new, either to the field, or the service, and you shouldn't know all the "ins and outs" yet. It's our job to see the competence level and assist you in learning what you need to know to either pass your class, or function independently.
I'm a county preceptor through the paramedic level in the county I work and volunteer in, and I'm told my approach to precepting is pretty unique. I tend to let the person function until they have a problem or feel uncomfortable. I give them a signal to use, so if they get stuck or in trouble, no one but us know there's a problem and I know they need me to take over. I try really hard not to step in unless they are really having a problem or just going down the wrong path. My goal is to build confidence, not tear it down. I get the most success and have the happiest students. It also makes me requested pretty often.
There is no compensation for precepting in my area. I don't get the extra money when I work, and I will spend countless hours at my volunteer station if someone needs runs and hours. I do it because I like teaching, and honestly, I love seeing new students get their feet wet and discover how cool this job really is.
I don't have any words of wisdom but to say, we are not all like that. I'm sorry you have had this experience and I hope if you're under an FTO again you get one that is a little more of a builder and less of a breaker.
Good Luck!