Then why did you bother to ask online?
I would say you are erring toward Jansenism, or at least a very rigorist approach to things.
Here’s the idea:
An obligation to attend Mass is a discipline of the Church. It hasn’t always been one. The obligation is a relatively recent development in church history. The obligation could be dropped tomorrow.
There’s an old canonical principle that favors are to be multiplied and burdens restricted. If a law imposes a burden, it is to be interpreted as strictly as possible. If it grants a favor, it is to be interpreted very broadly. Relaxing an obligation is a favor, so it can happen under the broadest of circumstances. So if you go somewhere that Mass is not available, you aren’t able to fulfill the obligation, so the obligation does not hold. Those able to dispense obligations can do so quite readily for almost any reason, though I have run into almost no cases where it was even necessary. Most of the time, if someone was impeded from going to Mass, even willingly, it wasn’t a situation where a dispensation was called for.
You seem to be conflating a disciplinary practice with something that would be an absolute good. We are under no moral obligation always and everywhere to go to Mass no matter what, or else the law would not allow for a relaxation of the obligation sometimes. As for why this is okay, it’s better to have standards the help keep us on the path that can be lightened as much as necessary, than an untenable set of rules and regulations that would just enslave us. Law is meant to direct us toward the good, not to be served as an end unto itself.
I’m not sure how to make it any clearer, and I realize I’m on the internet, and I only have a mere Master’s degree (well two, in theology, with another in Bioethics in progress) and only a mere four semesters of Canon Law. But I hope this helps.