I don't mean to derail the thread or be especially hard on the poster but I think some of the photos in question were taken unnecessarily close to the workers who were on site, particularly when there are so few people around in the shots that it looks like it would be easy to avoid capturing them altogether.
I seem to be in the minority here and as others have pointed out legality is a totally separate issue. I'm certainly not suggesting the pictures were illegal, I just wonder if they were taken in poor taste. One poster mentioned there being no expectation of privacy in public settings such as Nathan Phillips Square. I agree and don't think any rational person would object to their picture being captured as part of a wide shot there. But a closeup from seemingly 5-10 feet when they're not in front of anything particularly interesting? I think that most people would view that as off-putting (there's even a good chance they thought they were the subject of the photos, not the construction materials in the background).
Another commenter mentioned that the workers almost looked like they were posing - I agree, but I'd submit they might look like that because they're aware their photo is being taken and are uncomfortable while it happens. Obviously I wasn't there and I could be totally wrong, but I'd probably have the same reaction in the circumstance. If the picture taker said they wanted to get a shot of whatever I was standing in front of, I'd probably move out of the way and give them a better shot.
Again, I wasn't there and don't know the circumstances. Maybe the poster communicated to the workers that they're interested in this construction site and was taking pictures of its development and offered the chance to step aside while they snapped a few quick pictures. That's fine, obviously. But I wonder if they just walked up and started taking pictures in a way that unintentionally made the workers feel uncomfortable. I probably wouldn't speak up here ordinarily (I have, what, 2 posts ever after about 5 years of following these forums?), but I wanted to support
@khris here as I view their comment as totally reasonable.
Once again, my comments are based on the (possibly incorrect) assumption that the picture taker didn't communicate their intentions. I could be totally wrong and the workers were given the opportunity to get out of the way and wanted to be in the picture. If that were the case, then maybe it wouldn't be a bad idea to post a quick note to that effect, sort of like how people will post a picture taken from a car and make sure to add that they were not driving.