1) You can't capture a lot of this stuff. That's why we plan to de-orbit it before its even launched. The speeds involved don't bear thinking about (one screw in orbit can tear through the Mir Space Station like it was butter - how so you capture that?) You'll notice that it's incredibly rare that we ever dock with a satellite or other orbiting thing unless both are fully-working and we can use both their propulsions and PLAN IT METICULOUSLY. One wrong move and you kill yourself, de-orbit the satellite or add to the space junk ten-fold.
2) There's no value in them. Their biggest cost is launch, yes, but the actual satellites would cost hundreds of times more to capture and even more to repair than just binning them an launching another. Again, this is why we just de-orbit things into the atmosphere and let them burn up.
3) "Refuelling"? Seriously? Most of the "fuel" is either highly radioactive in the old ones, or solar in the new ones. The power isn't the problem. It's the cutouts, safeties, orientation to the Sun, etc. that kills off a satellites power, not it running out of juice. The Voyager spacecraft are still running at something like 50% power while on the outside the solar system 40 years after launch.
4) Who owns that stuff? Who will fund you to repair that stuff (much cheaper to just launch newer kit)? What if you touch a Chinese satellite by mistake? You could seriously start a war by just touching someone else's satellite, even by mistake, or causing debris from your operation to interfere with their kit.
5) Where would you repair it? In space? Via a spacewalk? The single-most-expensive venture that one man ever performs? You know the greatest risk while you're on a spacewalk? Getting hit by space junk that's so small and fast we can't track it. Are we repairing random bits of kit that were fabbed in semiconductor labs with the latest technology from inside an astronaut's spacesuit? Or would you take it to an in-orbit space station that would cost more to build and operate than it would ever cost to relaunch all those satellites put together? Or would you bring it back through our atmosphere at huge expense and risk only to be told that the technology was obsolete and that if they were going to have to launch it again, they'd rather do it with a new model or one that hadn't already broken once?
There's a reason all that space junk is called junk. It effectively is, because of the content, accessibility, and cost of going near it. It's like saying that 80% of the world's gold is in the ocean. It is. It will be. Until we work out a cheap way to drain and search the entire ocean for less than the difference between the total price of all gold on land and the total price of all gold in the sea.
The safest thing to do with space junk, even with politics and cost aside, is to push it into our atmosphere. But only to get it out of the way so the next launch doesn't hit it.