This article at the end mentions a famous Halachic distinction made between the prohibition of 'Ever Min HaḤai as it pertains to Jews vs gentiles. For gentiles 'Ever Min HaḤai doesn't apply to milk, because it isn't connected to the animal. For Jews, however, there is an added stringency that includes even the milk, which is why the Jews needed special dispensation in the form of the verse that praises Eretz Yisrael as the "Land of Milk and Honey". For this reason, according to the article, Bnei Yisrael never ate dairy prior to Matan Torah, which we commemorate by eating dairy on Shavu'oth. But isn't this internally contradictory? Bnei Yisrael had the same level of 'Ever Min HaḤai prohibition as gentiles prior to Matan Torah!
I checked the source mentioned in the article cited:
Reason #7: Rabbi Shlomo Kluger (HaElef Lecha Shlomo – YD 322)
You can read it yourself here.
Rabbi Shlomo Kluger says that non-Jews could drink milk, since milk is not a limb. One of his proofs is וַיִּקַּח חֶמְאָה וְחָלָב - and Avrohom fed them butter and milk!
I do not see any mention of the articles conclusion
that day at Sinai was the first time the Jews ate dairy products, nor do I understand how it is reached.
From what I can see, he does mention that
Bnei Yisrael had the same level of 'Ever Min HaḤai prohibition as gentiles prior to Matan Torah!
The question now becomes, where/how did Rabbi Shraga Simmons get his Chidush of
that day at Sinai was the first time the Jews ate dairy products.
Added on 4 Sivan 5773:
I received the following response from Rabbi Shraga Simmons:
Regarding the article, http://www.aish.com/h/sh/r/48969771.html, you questioned the source for reason #7.
Rav Shlomo Kluger resolves the Rosh Yosef's query that a Ben Noach is not commanded with Basar Min Hachai -- given that the gemara Bechoros 6b does not use the verse in Bereishit 18:8.
However, for a Jew (Avraham observed all Torah prohibitions and was in fact "Jewish" -- see Chidushei HaGriz on Sotah 9a ), it was surely forbidden to eat Basar Min Hachai, which at the time included milk as well.
I hope this helps explain.
Rabbi Shraga Simmons
I have not had time to study the response, but I do want to record it.