Eating dairy on Shavuot

There is a universal customs among Jews to eat a dairy meal on the night of Shavuot. There are a variety of explanations of where this came from. For me, the most convincing is the following; because that’s what the Jews ate the night they got the Torah.

Until the Torah was given, Jews were not obliged to keep kosher. But once it was reveled on Mount Sinai, the Jews had to keep kosher. So, of course, the Jews would have had no kosher meat prepared to be eaten that night (since it takes time to prepare meat in a kosher way). So the Jews could not have eaten meat that night. Hence the dairy meal.