Need advice. Is this irresponsible behaviour from the hike organisers or am I overreacting?

Context: In my country, there are these hiking groups on Instagram & Facebook where you pay the organisers a certain amount and they provide transport on a bus from the capital to the trailhead, meals, a local guide and basic safety & first aid. The group on each hike is different, although there are a few regulars who come on most of them. This particular group was about 20 people, a mix of experienced & beginner hikers.

I've hiked with this particular organisers 7-8 times now (on varying difficulty levels) and everything was good up until yesterday's hike.

This was a waterfall hike and they told us it was 15km (9.32mi) one way but the terrain was not difficult. We started at the trail head at 7 AM. Now, I'm by no means a pro hiker, but I don't think I'm an amateur either. The trail was quite difficult(although well marked in most places) and it was more complicated by landslides that affected the area 2 months ago. Their plan was to reach the waterfall by 11AM but by 12 we were still 4-5km from the end point. At this point I asked them if we should turn back, because it would take us the same amount of time if not more to get back & it would be dark and we didn't come prepared to hike in the dark. They dismissed it with something along the lines of "we'll manage somehow".

We reached the waterfall by 1.15 PM, was there for 45 minutes only because the local guide insisted we have to leave at 2 PM at least to make it to the safer part of the trail. We did manage to leave at 2. I and 3 other of the more experienced hikers went ahead with the local guide. We managed to reach the safer part of the trail before dark, but still had to go 3-4 km more on the train in the dark with out phone flashlights. The local guide said he told the organisers everyone should bring a flashlight (this message was not conveyed to us and when asked later the organiser's response was "I didn't want to scare you guys"). An old knee injury I had came back (because of course they do on the worst possible moment) and the rest of the way downhill was excruciating. I slipped and fell once, lucky with only a scraped elbow & a broken watch strap. There were several other people still behind us, the organisers were with them presumably and the guide also went back to help them. Luckily we managed to get back to the trail head without further incidents, although I'm going to need physiotherapy for my knees.

My question is, is this reckless behaviour on the part of the organisers? I seem to be the only one to think so. The other dismiss this as something regular that would happen on the trail & part of the "adventure". Am I overreacting? I feel like I need to say something to the organisers. Should I say anything? If yes, how should I phrase it?