How can a page be blocked by robot.txt without having one?

I consider myself a pretty tech-savy guy and easy at troubleshooting things. So WHY is the e-commerce system built to be so complex, so ridiculously chaotic for in which, I just get angry for there is no direct answer, no simple step. You need a third party to handle a process in which you need in order to operate on your platform, for it is not provided in your subscription. HOW DOES THAT MAKE SENSE? And the third party is OWNED by the PLATFORM, yet they don’t let you know it. And if you made a mistake, oh well… it’s like a parent scolding a child but never telling the child what they did wrong. So HOW am I to learn what not to do again? I’m rarely every angry; this entire experience the last few months has created many angry days. I guess it reflects how the world operates. You need a new medication to handle a side effect of another medication. You spend hours on hold for support, only for them to tell you that you need to be transferred to the right department. When I went to Toronto for the first time, it took me 30min to figure out their subway system, so naturally being from New York, you’d think we could figure out ANY system after mastering the M Line. After the 30min were up, I finally realized why it was so confusing: IT WAS SIMPLE. It was a simple, logical grid that worked efficiently. It was not made to create chaos or confuse the hell out of you, it wasn’t even designed to present you to advertisements or stores. We can’t think simply. Ok, rant over. I need to ask:

Does anyone know how the front-door can I find out how a page can be blocked by a robot.txt when you have no robot.txt ?

robots.txt have been editable for some time https://help.shopify.com/en/manual/promoting-marketing/seo/editing-robots-txt

Shopify is a proprietary system so it’s rules of how things operate are their judgement and built for them to support in the way THEY need to support it.

If you want a system you intuitively understand you have to be the one to build it.

To embed shopify in other systems you can use shopify buy buttons or the storefront api for more custom experiences.