First, I found HTML really hard to learn, I actually just ended up copy pasting codes to get it to work so that prob tells you about my knowledge of game programming...
Don't do that. At the very, VERY least copy the code by hand rather than copy-pasting it. There's a difference between seeing what an example does and seeing how an example works.
I heard python doesn't deal well with alot of objects on screen at once
Python is an interpreted language. This means that it is slower than something that can produce a .exe in machine code. However Python is also much easier to learn and faster to write than, say, C++. If you're going down the programming route, the last thing you should be worried about is "how fast will my game go" when you still haven't even written a single line of code. And you will not hit Python's limitations for your first project, or a while anyway; gotta learn how to walk before running.
I've been reading over the Danmakufu thread, and the language it uses (though it's supposedly simplified) is still pretty complicated, so I thought maybe I'd be better off learning one of the other languages since they seem just as complicated, but they may as well be 10x harder I have no idea
They are 10x harder. And that may be an understatement.
Danmakufu sets out EVERYTHING for you and leaves you to fill in the blanks with some code. You don't have to worry about getting a graphics engine working - there's already one. Music, sound, input, sprites, the overall game logic, all of that is already done. And better yet, the scripting language used is made especially for shooters - you can create a bullet using a single command.
With, say, C++, you start with a blank slate. You need to add all of this stuff, and C++ was not created with shooters in mind. It does not know what a bullet is, what a bomb is, what the player is, what an enemy is, or even what an x/y position on the screen means. All of this must be programmed before you can even get to a state where you're able to do the same stuff Danmakufu does out of the box. And then you still need to use C++ to produce your game's content - there's no command for "creating a bullet" or "aiming at the player", all of that, too, must be programmed before being usable.
On the other hand, a programming language gives you control that Danmakufu does not allow since you built EVERY aspect of the game yourself, not just the spellcards and players/enemies. Which also means you can manipulate EVERY aspect of the game however you want it.
I didn't think game programming was so complicated, I read a few danmakufu beginner tutorials and is everything really just coding stuff in a textpad with image files? all the effects and stuff etc?
The idea behind a program is to give the computer a list of steps to follow which explain how to do what you want to do. Your computer does not know what a bullet is, or that it's supposed to move, or that it can kill the player on contact. Or even what "drawing an image onscreen" or "playing an MP3" means (though you can generally find libraries someone else wrote to do these things; on its own, C++ has noooo idea what a png or a wav are).
The bottom line is your computer is dumb as a sack of bricks and needs to be told absolutely everything. Which, you quickly find out, is a lot. However, the neat thing is that you can generally reuse code from one project to the next so over time you build up a nice little library and can eventually almost skip straight to the game logic itself.
What you should go for depends on your goals.
As a hobbyist, Game Maker and Danmakufu are easiest to learn and will allow you to see results in very little time. You will be limited by whatever program you use but you should generally have no problem working your way around those limitations. If you "randomly decided you wanted to make a game", this is probably your best bet as you'll get results fastest.
If you want to work on more serious projects, learning a programming language is the way to go. This will take time and effort to properly learn. Your best bet is to start with a small, simple language and learn the idea behind program logic. You'll then easily be able to move on to more powerful and capable languages (say, C++/C#) and slowly work your way towards big and involving projects. But again, you will not see results as fast as you would with a 'Maker of some kind.