How do we understand molecules or cells? Through microscopes with our sense of vision? We haven't avoided the subjective sense problem at all! Merely refined it. We _can_ see the molecular machinery of the cell, having the ability to augment our senses with technology, and what we see must account for human subjectivity in a myriad of ways.
Math is a more interesting case, in that regard, as it is more clearly divorced from sense data in the classic sense. Though with the nondual perspective being presented here in mind, thought and logic is often lumped in closer to being a kind of sense - I don't _think_, I _experience thoughts_. I'm not settled on the point, but that framework would allow us to say "math is a function of the way human brains sense logical resolutions among axioms".
What makes you think humans are wired to experience objective truth?
Evolution is a process that builds agents capable of interacting with their environment in limited ways - specifically those ways that are beneficial for their reproduction and the maintenance of the species. If simpler (ie, subjective) degrees of truth are sufficient for humans to survive, doesn't it seem extremely unlikely that we would be given the keys to full objective truth? It can be very simply proved that even your sense data, the most direct and true-seeming aspects of our experiential reality, is subjective, rather than objective (eg, blind spots in your eyes that your brain paves over, various forms of visual and auditory illusions, phenomena like tinnitus and migraines that are responsive to feedback loops involving your attention, etc). And of course, we are as humans, subjective and biased observers of our experiential reality as well. If God himself came down on a mountain in front of 100 people, you would get 100 unique reports of how that encounter happened and what it meant.
You can come at this from a sociology of knowledge perspective - what we call "objective reality" operates more like "consensus reality" - the set of subjective truths that are widely experienced by people. In most cases, we can act as if these things are equivalent, except of course, for this type of philosophic enquiry!