Using such words as "conquering X" can happen in euphoric moments where you make small progress. It can be taken as how you take things not literally in poetry.
I would guess that if you were to ask the author, they wouldn't trivialize what one does in math grad school. The blogpost is probs best read as a personal story than a statement about math as a "discipline" at large.
I'm sorry that you were offended, math as a discipline is definitely misunderstood and the people working in it maybe moreso. They make contributions that allow truly cognition-breaking changes in other fields, and of course looked at independently the pure elegance and fun of it is beautiful...
If you have seen this beauty, why would you be mad at someone that dares to come check out your space? They are in awe at the art in your hallway (trigonometry) and exclaim "your home is beautiful." (discipline) Sure they haven't seen your pool and kitchen and everything else, but their compliment can still be met with gratitude.
In the space of eventually consistent communication among asynchronously thought-processing agents (aka. "Humans"), allowing for error induces less anger in general.