Having a teacher is not bad but you have to choose a teacher by considering all these factors like how good the teacher is or how much knowledge he has. Because out of all the teachers we see in the crypto world or those whom everyone considers as teachers, about 80% are scammers. The job of these scammers is to encourage everyone to invest in fraudulent coins by lying and making everyone buy these few coins.
You cannot always depend on the teacher, but rather, research everything the teacher has taught from other places and see how effective or good what your teacher has taught can be for you. At the moment, always keeping an eye on Bitcoin is the best decision and I myself always keep an eye on Bitcoin and try to keep myself away from all other coins.
You are right though. That is why the students also have their own role to play, which is to do their own research to confirm what their teachers said, like you highlighted, so that they won't make any costly mistakes. Relying solely on teachers because they are more experienced could lead the students to make costly mistakes, as no one is perfect in this world. So taking the necessary steps helps prevent unnecessary losses or damage. Also, in crypto one has to be smart and patient, otherwise they may get scammed.
Students or the learner at times feels like their mentors or teachers are 100% right , so there's no need for them to make research on their own. Instead rely solely on what their mentors teaches them. In the Crypto ecosystem alot of mentors are just desperate to make money off their students through payments for courses and private mentorship without even passing out good information to them. I remember when I first learnt about crypto, the guy I and my friends paid money to teach us, was just a fake guy disguising as a Crypto guru. That guy told us that if we invest our money into crypto today(especially in Altcoins/ memes), we will see massive profit, he showed us screenshots of his wallet and so many things then. We were naive to believe, which made us to lose money but that alone has taught me a great lesson to always teach yourself even after learning from someone, because it's not eveytime that they are right.