First, I practice judo and not BJJ, so understand what I can and cannot answer with knowledge and where my potential biases may be.
Second, this is a common way to start an internet flame war.
With that in mind, I will still try to answer this objectively.
So is Judo better for self-defense while BJJ is better for a controlled sports-setting?
Modern judo is sport first
Modern judo is definitely a sport first, and self defense second at best. Judo was organized with two primary forms of training: randori (free play) and kata (forms). Relatively safe techniques were practiced in randori with full speed and force while striking was relegated to kata. Even in kata, however, the striking elements are represented in caricature form; they represent an abstraction of how one should deal with strikes telegraphed well in advance, and you should not be under any delusions that judo kata trains for performing strikes. In modern judo, it's not really until the dan-ranks (black belt) that some judo players start worrying about kata anyway. Even then, mostly no one cares if you are a kata champion, but people care if you are a competition champion.
Modern judo practitioners start from the mindset of competition. Some never leave that mindset, and some even consider judo to be purely sport. While Jigoro Kano, the founder of judo, was still alive, he lamented the overemphasis on shiai (contest judo).
Sport rules protect poor self-defense strategies
Sport fighting will always be a poor approximation of real fighting, but strategies that optimize for sport rules may leave obvious holes in self-defense situations. Examples:
- judo: attempting to throw, failing, and turtling. In judo, this frequently employed sequence usually results in a referee stopping the match and restarting from the standing position. In a self-defense situation, this would result in getting your head kicked in.
- BJJ: pulling guard and fighting exclusively on the ground
You can train either judo or BJJ while avoiding these and other poor self-defense strategies, but this is not inherent to either system. And within the modern sport-centric cultures, it is probably difficult to avoid the sport-centric approaches.
Takedowns + submissions is poor model for understanding judo v. BJJ
There are four ways to win in judo:
My understanding is that BJJ matches are basically won only by submissions, which includes judo chokes and armlocks, but also leg locks, ankle locks, wrist locks, and some chokes that would be illegal in judo. From one perspective, judo has more ways to win, but from another BJJ is more specialized. You expect the specialists to be better in their specialties.
Judo emphasizes stand-up more
In judo you can win from stand up. In BJJ as far as I know, you cannot. So yes, I would agree that judo is more mobile as a result of training more from a standing position.