There's a whole category of seats not covered by your links. Large seats that are forwards/backwards switchable so they last a few years.
The seats are tethered to the safety latches, which although they are an "easy click" (two) can be quite tricky depending on the car and the tolerances involved. If the seat is facing forwards, it is also tethered to the sash belt, which I believe is the cause of "skinned knuckles" reference.
I 100% empathize with the person you replied to, and found your comment to be a bit dismissive in the "well I don't have a problem" fashion.
We have that kind of convertible car seat. Never had a problem with latches or straps (well, other than yesterday, when I had to take it out to fold down the seats & transport a piece of furniture). The car seat stays in the car, the kid plops down in the car seat, and then he either fights us over the 5-point harness or buckles it himself, depending on mood.
I think the big difference in perspective is whether you just leave the car seat in the car or take it out for every trip. I had a similar discussion on Facebook where I was like "Why does it matter how heavy the car seat is? It just stays in the car?" and then found out that a lot of people detach the carseats and lug them up to the house and back down every time they take a trip.
There's an element of privilege in being able to afford a complete set of car seats for each car you drive, but it totals about $300/kid (less for infants - many infant seats have a clickable base that's ~$100). If you can afford it I would highly recommend it - paying $300 to avoid daily skinned knuckles & schlepping 20-30 lbs. around is often well worth it.
I 100% empathize with the person you replied to, and found your comment to be a bit dismissive in the "well I don't have a problem" fashion.