I think this is a brilliant statement by Arnold.
If a thing is different from our wheelhouse of experiences or passions; it's easy to dismiss it &/or think it is weird. Even condemn it, "That's ridiculous! They are stupid."
When I was an avid bodybuilding student - bro-science was gospel. The most scientific research was laughed at if delivered by someone that wasn't of physical stature. We'd make fun of our powerlifting friends for having higher body-fat. We thought our running friends were misguided, "Bruh, I see you doing cardio, what show you doing... You just like it?" *cough-"weirdo"-cough* And 20-25 years ago I hadn't heard of Crossfit. Some of our buddies would do similar workouts; but they were usually in some type of team sport practice. But don't worry, we made sure to tell them they were missing out on their gains.
After about 17 years of re-reading the gospel of Arnie's Modern Encyclopedia over and over again; I tried a powerlifting. At first it was weird. I had to "relearn" how to bench, how to squat, and the difference between RDLs and real deadlifts. Once I did my first powerlifting meet, it was like drinking the koolaide. Now strength and "movements" were king. We made fun of our bodybuilding friends because they wanted to be so pretty. With their tanning, shaving, gloves, lifting straps -etc. We'd tell them they couldn't do proper lifting movements unless there was an isolation machine for it.
Then we moved to SoCal..
I got into kettlebelling - I shed the straight-jacket of a traditional gym workout and frolicked around the sunny parks and beaches of beautiful Santa Monica. I'd like to tell you that by the time I made it to kettlebells I was so mature I didn't make fun of anyone. But I am sure I made fun of someone.
I want to point out it isn't bully type of making fun of... it's friendly banter. You enjoy what you practice and you want your friends to join your party.
As I have grown so mature over the years *smug face* I try to encourage rather than make fun of other "genres of strength fitness". I still have my favorites; and depending on the season those favorites can change." All modalities can be silly at their extremes. All modalities can be dangerous if practiced without focus and discipline. All modalities can encourage the human body to adapt to the imposed demand. All can be extremely rewarding to the practicing individual that enjoys that modality.
I think Bodybuilding is awesome, I had a lot of fun doing it. If you want to compete, you can spend 5 to 7 days per week training & eat like it is your part time job - godspeed, & I'd love to share my mistakes so you can learn from them. Powerlifting is your thing - terrific, I love it. It is amazing to watch -and a rush to participate. Crossfit has done an outstanding job branding and marketing itself. Even people that have never seen a weight or a gym, know about Crossfit. I have good friends that are Crossfitters that have built an impressive level of fitness. Strongman - I think is really cool. The times I have gone to watch in person was a bit slow going because they have to keep setting the events up. But on TV where that part is edited out and it's all action -that's awesome. Kettlebells can be fantastic tools that if practiced correctly can be amazing minimalist tools that can yield some awesome results and can free you from needing a gym. Calisthenics!? Go to Muscle beach in California and watch some of these guys and gals.. amazing!
I could go on. But for me it boils down to any on these subsets or "genres of fitness" will have it's own pros and cons. I believe that any of them coached poorly or practiced with bad form is asking for injury. Coached correctly they can all be safe, fun, and progressive. Practiced with focus on intent and form - all can lead to progress within the practice.
At the end of the day we are all weirdos to the folks that do not exercise. If you rid your language of your personal biases and explain at it's root (get it down to it's lowest denominator) the goal of the practice of strength development you choose, I think they would all sound a bit like, "Improve strength, improve physique, improve performance, improve movement form, and prevent weakness." With maybe from time to time, an added, "look cool" &/or "feel good/great"!
I think all should practice parts of those 5 points and the 2 bonuses are always gifts that should be opened from time to time. Now these 5 points will be relative to every individual. And perhaps that could be an entire separate discussion. But for quick example "improve strength" could be from helping someone relatively immobile, be and to sit and stand (or) get down to and up from the ground, better. Or it could mean strength endurance. Or of course maximal strength. "Improve physique" for a body-builder could be lower your body-fat percentage as low as you could get it. For a powerlifter it could be gain muscle; strongman bullet proof your joints/lower back.
We are all weirdos.