Always hated breakout board producers for this pull-up resistor thing, especially since they are often targeted at the educational market. Why would you solder fixed pull-ups guaranteed to work only when it's just you in the bus (and not even that as it's pretty common for uCs and SoCs to include their own pull ups)? Teach your users the simple calculation needed to add pull-ups themselves!
It's way easier to remove a pull-up resistor that's present and undesired than to add one that you don't have in your parts stash. And there's way more beginners/hobbyists who won't have one and won't understand why their board doesn't work (and think your board sucks) than people who will have their circuits not work for unknown reasons when they stick multiples together.
By the time you're doing that, you're probably reading someone's tutorial on how they did it and monkey-see, monkey-do, or you're far enough along in your learning journey to know to desolder some of the pull-ups.
Arduino "won" by making things dead-easy to get working for people who frankly didn't have a clue what they were doing. This is a good thing, IMO. If it works straight away, you learn something and are inclined to take the second step. If the first attempt starts with a theoretically better lesson on how to calculate, select, order, and solder pull up resistors, you're failing at user engagement and unboxing experience by more than than you're gaining in theory-learning.
Partly agree, but it's not like you don't have to use resistors anywhere else with Arduino and the likes.
Just to light up a LED you will need some and usually there are plenty included in starter kits. At least where I live there still are a couple of electronics retail shops where you can buy spare components.
Also arguing that desoldering smd resistors is easier than finding a through hole one and plugging it into a breadboard or soldering into a prototype board is a bit of a stretch.
