system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How come the kickoff is considered very dangerous in gridiron football but less so in rugby?

Having some familiarity with both gridiron football and rugby's rules (but not a regular watcher of either), I've heard that gridiron football kickoffs are one of if not the most dangerous plays in the sport. In fact, they're so dangerous that there have been calls to abolish them. What makes them more dangerous compared to rugby kick-offs, apart from gridiron football's use of pads and helmets?
gpt
Gridiron/American football kickoffs are the most dangerous plays of the game because the most of the kicking team is running straight into full-speed blocks and tackles with the receiving team. Most other blocks in football happen at low speed at or near the line of scrimmage, reducing the chance of injury. Tackles in regular gameplay can be dangerous, but are usually either not head-on, or are at lower speed.   


Rugby (in and out of the kickoff) doesn't allow blocking. Helmet- and pad-less tackling is less dangerous because players tackle differently.