It is from the Moon's perspective. On the visual spectrum the Earth is much larger and more reflective than the Moon. You're looking at something like 40x greater illumination during a 'full Earth' than you get during a full Moon on Earth. Earth is also extremely noisy in the radio spectrum for radio telescopes, while the Moon itself blocks most of all of that out on the far side.
Earthshine is brighter than moonshine, sure. Earthshine at its brightest, delivers about 0.15W/sq meter to the moon. Sunshine meanwhile delivers 1360W/sq meter to the moon. The near side of the moon is the only side which experiences eclipses. The amount of energy from the sun is SO large, compared to earthshine, that ~1.5 eclipses per year for a few hours each represents a loss of light that outweighs the additional light gained from earthshine by about 5x.
We're talking fractions of a percent here of course, but it's not ambiguous. The near side of the moon is also the darker side.
Details for why ~40x: The Earth is 3.67 times larger in diameter in the lunar sky than the Moon appears in ours. Earth covers 13.5 times more visual sky area and is also about 3 times more reflective per unit area
As I mentioned in a sibling comment, the brightness of the Earth does not outweigh the lost sunlight during lunar eclipses. The near side of the Earth is darker.
By the time we have a radio telescope on the far side of the Moon, I assume we can just lay a couple hundred kilometers of fiber to the nearest settlement. The border of the disk, from Earth's perspective, is prime scientific real estate - the border of the area that's always visible is not too far from the area that's never visible (and, therefore, shadowed from our radio noise).
Maintenance crews can do quick hops to the telescope, while their offices are always in contact with Earth.