Earlier quoted context omitted.
ICMP (the protocol ping uses) is a totally separate protocol from TCP and UDP. Blocking ICMP can break of lot of things and offers no real benefits outside of a handful of specific edge cases. BTW your assumption "a successful ICMP ping = TCP and UDP work" is an extremely common one that I too had before I was taught otherwise.
> Blocking ICMP can break of lot of things and offers no real benefits outside of a handful of specific edge cases. Are you referring to local networks only? It's very common to not allow ICMP by defaul to workloads in the cloud, e.g. in AWS.
Edit: here's a good page about the effects of disabling ICMP: https://www.rimscout.com/why-you-should-not-block-icmp/
Also there's some blackhole detection or how is it called.
However it's OK to block _parts_ of the ICMP protocol for security reasons, like echo and reply.