http website marked as "risk"

The "risky" is just a standard warning. You can ignore it if you are sure about the website. Because nowadays https becomes the standard.

It's marked so that if the site actually WAS containing forms/logins, and not being secured means it could have been changed in transport freely without anyone noticing, this was to warn users normally used to it being secure it's not now. (There's also the nuance about unsecured traffic being easy to observe and monitor for anyone along the line.)

But you're completely right just by securing the connection doesn't mean sites are safe — they can still distribute malware, phish et al. but there are other mechanism for that, albeit reactive.

Mozilla was a founding member of abetterinternet.org so that TLS certificates can be omnipresent — today getting one for HTTPS service comes without a cost. Might be worth considering letsencrypt.org if the warning is bothering you.

indeed, when I got deeper into the website, there is an (inactive) Facebook comment plugin and donation button. I think if I remove these elements, the site will be marked as safe. Anyway there are no such objects in the main page that I opened by typing the start page URL.