TLS could be the most flawed system on Earth and it would still be better than no TLS. Plain traffic is just that, plain. I can do whatever I want to your web browser as I can arbitrarily change the contents of websites. I can make a page be full of ads or do more malicious things such as replacing a page with a phishing site or running something like beef which allows me to have full control of a browser and to pull all information. I could also exploit any vulnerabilities in the browser to do privilege escalation although to be fair major security CVEs are rare.

This is literally a community about privacy. I don't understand why you wouldn't want https. It works out of the box and it is implemented pretty much everywhere. If a site doesn't use it that site isn't really worth using as it take very little time to setup with Let's encrypt.