This allows steam network traffic to be intercepted. It can be fixed by correcting the URL to https.
For example, somebody using steam from a coffee shop could have his credentials/cookies/accounts intercepted by the coffee shop operator or any other visitor.
I believe coffees and other gaming venues are a supported use case for steam and you do not wish to leave your users at risk.
IMO There is really no need to blow this out of proportion. It's just a typo. Developers make typos all the time. Bet they're more likely to double check something trivial like that if pointed to.