You can also get started without understanding it all
I disagree with you that anyone can invest into bitcoin without have any knowledge of bitcoin at all. You must have the basic knowledge of bitcoin before you can start your bitcoin investment or someone is there to guide you. If you don't know anything about bitcoin, how will you know that you are invest in a long-term and that the price is volatile and you shouldn't sell in panic whenever there's a dip.
This is the reason why a lot of people jump into bitcoin investment and think that it's a get rich quick scheme and run at loss because they fail to learn the basic knowledge of bitcoin and understand how they can plan on investing and hodli for a long-term.
I can take myself as an example, in the beginning when I heard about bitcoin due to lack of the basic knowledge of bitcoin, I thought that it's only for trading and never knew that investing in it for a long term plan is the best. I also invested in shitcoin because I don't know the difference between bitcoin and shitcoin because I didn't make any research. Anyone who wants to start his bitcoin investment must have the basic knowledge of bitcoin and increase his knowledge as he is building his bitcoin portfolio.
I agree with all you just said, except for disagreeing with your quote on @cossyblack, he didn't say 'understanding it at all's he said 'understanding it all which would mean that he is in support of having basic knowledge of bitcoin before beginning and investment instead of knowing everything about bitcoin, so he is not saying anyone who doesn't even know what bitcoin is can just go in and start investing, you can't invest in something you don't know unless someone else is running your investments for you.
So going into bitcoin investment, you don't need all the knowledge of bitcoin in the world but you can't go in without any knowledge at all, you need to at least have a basic knowledge of what bitcoin is, this way you wouldn't just lump it in with all the other shitcoins out there.