The site is already available in HTTPS. Why would you even serve content non-encrypted?

If you need an education on the matter... Here you go. https://www.cloudflare.com/learning/ssl/why-use-https/

"I don’t handle sensitive information on my website so I don’t need HTTPS"

A common reason websites don’t implement security is because they think it’s overkill for their purposes. After all, if you’re not dealing with sensitive data, who cares if someone is snooping? There are a few reasons that this is an overly simplistic view on web security. For example, some Internet service providers will actually inject advertising into HTTP-served websites. These ads may or may not be in line with the content of the website, and can potentially be offensive, aside from the fact that the website provider has no creative input or share of the revenue. These injected ads are no longer feasible once a site is secured.
Modern web browsers now limit functionality for sites that are not secure. Important features that improve the quality of the website now require HTTPS. Geolocation, push notifications and the service workers needed to run progressive web applications (PWAs) all require heightened security. This makes sense; data such as a user’s location is sensitive and can be used for nefarious purposes.

I don't feel the need to be your teacher. You can easily google why you should always be using HTTPS. There's numerous reason... all overwhelmingly obvious. Forget the basic "Not every ISP is an angel, and they all will collect as much information as they can get". But I already said that... "It’s still best practice to limit sniffing." Not sure why I need to elaborate any more on that. Very much akin to "why close your window blinds", because nobody likes a peeping tom.

Ultimately for this specific website it's literally changing a couple lines of code in their apache or nginx instance (or whatever proxy they're using). It's called best practice for a reason.

Edit: Hell it's even a bit more of a guarantee that your site makes it to the consumer unaltered. Would be odd for that site to have it's packets intercepted and midget porn be added to every page wouldn't it? Think that would hurt the guys reputation?