“After all it says ain Simcha eleah Dag v’Basar”
ZeDa- It actually says Elah baBasar and baYayin. And, that’s talking about YomTov, not Shabbos, when it is a Chiyuv to eat meat and drink wine. As for Shabbos and fish you’re doing fine, you don’t like it, that would be hepech Oneg Shabbos.
Sam- are you talking about Y”D 341:1? See the Pischei Tshuva who is michalek between Shabbos and YomTov where there is a Chiyuv mitaam Simchas YomTov. And on Shabbos TishaBav and for an Avel there is a Chiyuv to eat meat, see Magen Avraham 13 in O”C 552 (and Machatzis Hashekel). And even from 341:1 I’m not sure it means that you *should* do what you want, maybe just that you could. See Tur O”C 242 where he says “Tzarich Liharbos” (and “Yesh LiAdam Lizarez Atzmo”) and Shulchan Aruch 250:2.
So sometimes there is a Chiyuv to eat meat.