I think the point is that dominion.isotropic exists and the only obstacle for it to continue to exist is Goko. Playing on Goko is, to some extent, supporting them (even if you do not spend any money, a big player base is a must to attract new playing people).
You can think of it as a Goko boycott or a Goko strike. You may disagree with some or all of the boycotting actions or the strikes, but at least some of those proved useful in the past, so I don't see how you can say they are "intrinsecally" useless. I guess the analogous more extreme argument against a strike would be "is better to have a lousy job with a lousy pay than no pay at all" and for the boycotts it would be "is better to pay the cheapest price for this shirt, why not buy the sweatshop kid-exploiting brand?". Of course Goko did nothing as bad as that (not even close), but the response against Goko some people have is also not extreme, and at least in my opinion, adequate.
For my own opinion, Goko did not work ok or better even once. Isotropic, on the other hand, works perfectly. When Iso is down if Goko is a nice activity, I may review my position. I doubt I'll get hooked up on Goko as I was hooked up by Isotropic, though, in the same way I was never hooked up on BSW, even though I've had regular affairs with many of the games they carry.