Even if you read the ToS, do you really expect people to remember this? CloudFlare blends into the background when setup properly, and you don't have to think about it. If you upload a big file to your site as part of some other work -- especially personal -- most people are not running through the ToS of every service that might be involved thinking about compliance.

Terns of service are also legal "CYA" documents. If CloudFlare was actually serious about that restriction, there'd be a technical limitation in place that would, for example, serve a 503.