Because for some people talking to strangers is hard. Literally - like for some people carrying a 50 lbs bag might be hard, so can be talking to a stranger. Can I take this 50 lbs bag and walk with you for a mile or two because you think it'd be fun for you? Yes, I can. Do I want to? Maybe, if you're my friend or I feel like working out or just in the mood. Or maybe not, because I don't feel like doing this work now. Maybe I just want to rest and be alone with my thoughts right now. Not for the whole life - but right now, in this moment.
People have different needs and different informational metabolism. Some like conversing with strangers, some - not really.
Reading this felt like you've been observing me at the gym and documenting my behaviour. I've been trying to establish an exercise habit and at some point I'd like to become comfortable again talking to strangers. It used to be a skill that I practiced unknowingly when I was young and could talk to anyone. Now there are days when I'm done working out and it takes all the effort just to make eye contact with someone and mutter something like "hey, how was your class?"
Don't get me wrong - many introverts can talk to strangers just fine if they need it (just as I can lift 50 lbs if I need it), it's just something they don't particularly enjoy doing. It's work. If it needs to be done, it will be done, but if it can be avoided - it will be avoided. I am not sure one needs some training to change that - if I don't enjoy doing something, why waste time on doing it if I could instead do something I already enjoy doing?
for an ice-breaker, dont go with an emotional check-in lol. much easier to say something humorous like 'fukin weights, bastards are gonna kill me rather than make me fit'
People have different needs and different informational metabolism. Some like conversing with strangers, some - not really.