I am not the OP. The terms indicate you cannot use it to proxy traffic to bypass bandwidth costs. The grandparent comment suggested using Lightsail to do this, and it is a violation of the TOS. The parent comment, however, stipulated that you are not allowed to use Lightsail at all, which is indeed wrong. I was just posting the relevant portion of the TOS which applies to the grandparent comment, and clarifies on the parent comment (which is inaccurate)
The clause prohibits you from using Lightsail to cheat other services. So, per their example, you couldn’t set up a Lightsail instance as a reverse proxy between the internet and an ELB, to take advantage of Lightsail’s higher transfer quotas and “in-region” traffic from Lightsail to ELBs.
Hosting a site on Lightsail and hosting other things on other AWS services is fine.