I disagree with Molly and think she's making a lot of assumptions.

As someone said, reading and watching videos only give you so much information. I think it's probably unusual for someone to get it on the first take from that, without being over-geared.

Not everyone takes in information at the same rate. Maybe you can read about a boss in 15 minutes, but how long does it take you to read about all the bosses in a dungeon/raid? And will you be using that information right away? If not, will you still remember it all?

The people you are playing with may or may not care. A non-hardcore guild doesn't necessarily mean they're lax on preparation, but either case is an assumption until you're told or ask. There is nothing inherently wrong with not doing your homework in advance, even if it causes wipes that you could be avoiding by studying.
Not wiping may be what you require to enjoy your experience, but it is not inherently so for everyone. There are some professional raiders who actually value learning strategies primarily by trial and error rather than adopting existing strategies from the start. While it's fine to have expectations, people should still keep an even head.

While your behavior affects other players, there is a large range of possibly acceptable behavior, and we also have to consider reality VS ideal. Some things you can change, while others you can not.
Someone may find it worse to spend twice as much time studying as playing, than to wipe, or possibly get yelled at and kicked by a group they're in. and the other players have to live with getting annoyed and having their time spent in this way after the fact. There is no single "proper" way to play this game. (Hardcore raiders may disagree. That is their prerogative; not mine.)