It is not called cockyness, it is like that to attract people to see it, because they will rather check 100% Game Winning guide in the name, compared to Shitbringer's guide. Among the many guides, you gotta make the difference. You could reconsider your vote mate.
As for the guide, I'd say 100g spent on wards/courier @0min is a bit low for VJ as a standard.
Also, I see a core of 4 items, which does not leave much room for wards, rev wards, homecoming stones and/or pots. Also, no mention of vestments.
People seem to disagree what "core" means, so won't comment on the 4-5ish kg core on a support.
I've put the wards and rev wards and pots in the core, and it is pretty easy to get 4-5k with proper supporting, as you can see if you review my games, where I have about that, whilst main carry has 20k farm or more in about 25-30 mins of the game.
Main reason is that due to massive amounts of ganks you will be doing and not going to base, you will really not have enough to use it. Even with the ring of sorcery and mana potions, with the speed of ganking that I do and that this guide is intended to make you do, you will really not have enough for Mojo until really late game. Also note that if palyed good, there will be no late game, because what usually happens with this tactic is CC 15.
Reason you win in 1700-1800 bracket is cuz u actually buy wards and gank for ur team. Many 1700 supports fail to do so, so ur more likely to win against them. Also, they often ignore calling mia or just lack map awareness in general. However, the story will be different once u get into the 1800s...
p.s. If the enemies are clever enough, they can counter gank u and u will basically just feed.
I feel like this guide assumes all of your ganks will be successful, which is pretty hard to count on if the other team is somewhat competent with wards and map awareness. If you're supporting your carry, boots by level 3 isn't always easy unless you get bloodlust.
I'll give your guide a shot when I get home to see if I like the playstyle, though.
Also, one little note, it's harder to gank hellbourne mid from bottom, and harder to gank legion mid from top.