I don't think anyone was was "insulting or rude" the OP asked for opinions. I have had five 5 year olds. By 5 all of them were capable of walking in the parks. By 5 all but 1 wanted nothing to do with a stroller (other than to push dolls in) because they were "for babies."
...but there was the last one. He refused the stroller, adamantly, from 2-4, but at 4 refused to walk LOL. When we went on his 1st stroller-less trip at 5 I sat him down and explained to him that we were not bringing a stroller (and after finally getting to be stroller-less we realized how much easier it is to not have to worry about it)
We explained to him that he would have to walk. We also explained that if he were that exhausted and complained, because he was complaining it was "too much walking it would hurt his legs" that one of us would take him back to the room for a nap, so he could rest.
We never had a problem. The only time we had whining about not wanting to walk, and that was from all the kids at one point or another, was between the bus and the room and the end of the night, and mostly that was because sound asleep on the bus and wanted to go back to sleep.
I have a bunch of kids. I get that they whine about being tired to get out of doing things they don't want to do, like, maybe, shopping, but if they are physically healthy, then there is really no reason that they are incapable of walking those types of short distances.
The OP may consider having a discussion with her child, I think 5 is old enough to understand a lot of things, and he/she may want to start a walking program with her child if stamina is really the issue, which it probably isn't.
Here is my kids behavior issues. I had 1 whiner, but I had 3 arguers. The 1st 3 are kind of close in age, and they used to bicker amongst themselves about stupid stuff. Who was 1st in line, who was touching who, you know, stupid kid stuff. I remember 1 trip to WDW where they were particularly bad while playing with those bead doors waiting in line for RnR. I finally had enough and told them that if they were so cranky and tired that they were arguing over stupid stuff like who is playing with beads on a door it is time to head back to the room for a nap and a cooling off period, and I mean nap. No swimming, no TV, lights out nap. It stopped. No one wanted to miss out on fun. They also know that when we say something we mean it.