sorry but that's bullshit.
don't be one of those guys who says they can "do anything high" and everyone should be able to too. Most people just say that as an excuse to justify their psychological need to toke every second.
Any indica dominant strain knocks me out and makes me stupid. It's just more difficult to process stuff. Some people can get away with it but weed effects everyone differently and for most people it makes doing tasks more difficult. I don't see the point in getting baked just to make something more challenging than it is. Just because you can do it doesn't make it a good idea
Smoking before the gym (when i actually used to go regularly) was generally a no no for me, unless it was something light like bi's tris or abs. Then yeah, there were times i was able to "get in the zone"
Any high intensity Olympic lift like deadlift or squats i'd be gassed and dead practically on warmups. Filling your lungs with carcinogens (unless you used a vape) is just retarded if you plan on doing heavy lifting. My workouts were pretty short but intense and involved going heavy....weed is a depressant so naturally it makes it more difficult to push through and keep pushing yourself when your body is ready to give up.
smoking weed after though is nice.
Ok I probably shouldn't have projected my own beliefs onto other people, since everyone is different and definitely have different reactions to intoxicants.
I'm sure you know medical marijuana users smoke literally all day, and yes, some of them are functional human beings that make positive contributions to society.
In regards to working out, I agree with you for the most part. I went through the same thing around 6+ years when I started doing it. I used to get tired and not push through workouts, but that's also because I was a novice at weightlifting. Not anymore. My strength, endurance, athleticism are all the best they have ever been in my life and continue to improve on a daily basis. I squat, deadlift, run distance, you name it. If there are any actual studies on if marijuana affects your ability to work out or build muscle, I would happily read them. I've honestly always been curious about the physical side effects, but have never experienced any negative ones.
edit: the comment of mine that you bolded was more directed at people that don't smoke and assume that if you do, you're lazy, sedentary, and unhealthy.