Why double down on this of all things? It's not even necessarily about a medical condition (but it's that too, for many of us it's not a skill issue but a heart and lung issue), it's about the fact that biking up a hill can be fucking hard and I wouldn't begrudge anyone for not wanting to do it all the time living in a hilly city, let alone if they're trying to get home after working all day and are dead tired. The person who you were first responding to, who was asking in good faith from everything I can tell, also said "how do elders deal with what other citizens would take for granted in terms of mobility?" You completely disregarded that. Would you tell your 80 year old grandparent just to bike harder in their hilly city? This is a totally legitimate concern and responding "skill issue, just bike harder" really is heading into some ableist territory.