Sorry man, but it's not about language affinity. It's about visas and work permits. It was much easier to get work permit in Russia than in EU for Ukrainians and it still does. But last two years things started to change, Poland gave about 1 million work permits to Ukrainians in 2015. So, no pain
Then more power to you. The Polish board is already available, so, I assume, you can safely start posting there, all the while the Ukrainian board is not a priority. That would be quite logical, since Ukrainian is closer to Polish than to Russian, right? You might even want to substitute Roman letters for Cyrillic script to get even closer than that...
Personally, I would be happy to see you and your buddy posting in that board
Sorry man, but your logic is very weak. There are around 2 million polacks in UK and Ireland, but Polish board is here. Think about it when you will have some time.
Should I assume that the next thing you are going to say would be a claim that English and Irish on one side and Polish on the other are mutually intelligible? This is what follows from your words. But since the Polish board is already present here as you yourself seem to confirm, we can safely assume that this not the case. On the other hand, you yourself said that a lot of Ukrainians working in Russia today is due to the ease of getting worker visas, and not because of the similarities between the two languages, right? In this way, you have essentially stuck yourself between the upper and the nether millstone. When I say that Ukrainians understand Russian perfectly (and this is one of the reasons why the Ukrainian board is not a priority), you start claiming that it is not so, and that Ukrainian is closer to Polish than to Russian. If you're okay with that, I see no reason why you should have any problem posting in the Polish thread then...
But I didn't see even a single post of yours there, while your buddy is actively posting in the Russian board at that