Yes. But for the moment there are really few tutorial videos for modding in 1.13 if you think you can do better videos (what is surely true, i don't doubt about that), well .. just do it instead of whimpering because it doesn't exist !
I'm not telling you can't give argue why this video is bad, the very part i can't agree is you tends to say this video shoudn't be "allowed" to exist. But fact is without this video, a lot of people just couldn't create basic mods in 1.13 today. As this video doesn't concern you (because it's made by a beginner, for begginers), you can give your opinion but you can't say it's not a good start. Because actually, it's the only start we currently have (pedagogically, it's a lot more difficult to learn by reading alone than being explained orally buy someone, that's why we have teachers).
It's not like programming a whole video game, it's just an item. I'm not sure the tutorial he made can occur any crash. If you find one, you win the argue. His code IS obviously a big MESS (even me can see it, while i'm a beginner), but not falty.
You are probably true for the second part, i already read the link and I get the methaphor. I even understand your apprehension about those kind of thing because i read A LOT of times on this forum "don't use ItemBase, don't use IIventory, don't use (dramatic music) IHasModel", and when people have bad habbit, it's hard to disassemble it.
But we (begginers) aren't all lazy guys who want you to vomit good the good codes in the mouth (there are some, i saw that), some of us (me) try really hard to understand WHAT you do and WHY you do this but we still need a start point to begin. And without this video, some of us just don't have one (as I said, there are really few videos of modding on youtube)
As I tried to say. It might be a start point : you write first, then you try to understand why things are like that. It's not the best start for sure, but it's the fastest, and if you just need to implement 2 or 3 simple items in your favorite video game, you don't need to learn ALL the programming part first.
Didn't you ever wonder why multiplication is communitative ? why 3*5 == 5*3 ? While division isn't ( 3/2 != 2/3 ) You just do this naturally because people told you "just do this, it works for me!" while you NEVER wondered why. The main answer for multiplication is because simple numbers are 1 by 1 matrixes, but usually, matrixes aren't communitative at all ! Did you learn what was a matrix before "communitatives" numbers in a mutliplication like you might do everyday ? I don't think so.
Did you already made an real experiment by yourself to be SURE the earth is round or flat or aren't you just repeating what you've been told all along and judging other people which doesn't think like you ?
Why do you say "hello" to people ? Why do you double click on your mouse instead of clicking once ? Why do you use shoes instead of walking without it, are you a dermatolog yourself to be SURE it's better ? Why do you vaccine ? Why do you cook meat isn't of eating i raw ?
There are A LOOOOOOOT of things we do without wondering WHY we do them. Because you are a doctor doesn't mean you are allowed judge people dumb because they don't know why they vaccinate, while you do know why. All of them don't want to become doctor either and DON'T NEED to spend weeks and weeks to understand why they need to do it, even sick people. You can't refuse vaccinating someone which refuse to know/learn/undertstand why they should do it. Maybe this person is a baker and he will refuse tommorow to sell to you his fresh bread because you don't want to know how to correcly cook it (i'm not talking about me, i don't refuse to learn code, it's an exemple)