Not a geologist either but an astronomer. Never heard that tectonic activity has any association with proximity to equator.
Mountains can rise higher near equator because you have the least gravity there. The whole Earth bulges along the equator. But I don't think it's measurable.
It's also interesting because the radius of curvature is smaller, meaning the distance to the horizon is shorter north south, and a lot of these views are north south. So the increase in mountain height more than overcomes the other effect!
The earth is an oblate spheroid to an approximation. It's not that they're not symmetric, but at the equator the north south axis has higher rates of curvature than anywhere else (but the east west has somewhat lower rates because of the larger circumference due to the bulge).
So that large lines of sight are near the equator on a north south axis (or symmetrically south north) is crazy because the high rates of curvature in that direction at those latitudes should give the shortest distance to the horizon on earth, making those lines of sight even that much more impressive!
While Everest (8849m) is the highest point above Sea Level, Chimborazo (6267m) in Ecuador is further from the centre of the Earth (about 2000 metres further), due to the equatorial bulge. It's very measurable.
Well that's not what the claim and clarification was about. The question was: can a mountain rise higher in the equator as compared to higher latitudes?
It is not about highest point from centre of Earth. That's is related to equatorial bulge but irrelevant to the discussion.
Mountains can rise higher near equator because you have the least gravity there. The whole Earth bulges along the equator. But I don't think it's measurable.