Hikes like half dome and angels’ landing are super dangerous whether or not people die frequently on them. You’re not stupid to do these hikes if you prepare for them, but even if you’re prepared, there is still risk.
These hikes can get crowded even with the ticket system, and more and more people rush up these trails to get the shot for their Insta or whatever. Two-way crowds of impatient tourists on these narrow ledges and steep scrambles/climbs are a real issue and even a prepared hiker could get unlucky.
Not to mention other hazards like incliment weather like in this case. Half-dome is a unique weather risk during that final climb because it is just rock. Rock worn extra smooth and made dusty by hikers’ boots. If it rains, that dust turns to silty mud and you now have nature’s most majestic slip-n-slide.
The national parks make nature accessible, and because it’s accessible, people underestimate it and don’t respect it like they should.