No, what I was saying was that you as a layman, making the call on Stam Yayin and other gezeiros of Chazal is not much better than my kid dismissing the doctors treatment. Your chavrusah may be a noted Dayan but if he is really the source of these ideas he would appear to be outside of normative orthodox practice. There were great Rabbis at the turn of the last century who tried to allow chalitza via messenger and using the bath in the home as a Mikva, and they had cogent arguments that they presented but their opinions were rejected by the overwhelming majority of the leaders of their generation.
There are hundreds of responsa written dealing with the longevity of gezeiros and takanos- and there are many many criteria- who established them, how widespread was there adoption, etc. For you to wake up in 2017 and decide that you know better than thousands of Torah leaders spanning many centuries ( there were strong reasons to permit wine in the time and place of the beis yosef as well) is presumptuous.
Now might be a good time for you to join the daf hayomi which is learning avoda zara and is just starting to go through yayin and a host of other gezeiros of Chazal and learn the rishonim and achronim on those sugyos to get an idea of how chazal formulated their gezeiros from authentic sources....
Stam yaynam pretty much took nesech and applied it throughout.
Inherently you should be able to buy wine from muslims if they had a winery.
Stam yaynam is illogical because, the prohibition was set to prevent intermarriage, yet I can and do drink with non jews, further if the wine is mevushal, they can handle it. If stam yaynam was the concern in terms of intermarriage, I should be prohibited to drink mevushal wine with a non jew.
Many poskim hold that a jew that is not shomer shabbat can handle the wine, in Israel and europe for example, many restaurants sell non mevushal wines, only in the USA is it a mishugas
These opinions are mine, not my chavrusas, they are stuff we discuss, i'm not saying he agrees or endorses my opinions but he doesnt call me a heretic.
Say what you want, but yayn stam makes no sense, i'm actually more likely to hook up with a non jewish woman at a beer brewery since we have no wineries here