Why were some Romans happy about being conquered by the Huns

Because Many people from the Roman empire believed that the Roman government was oppressive and that the taxation was over the top and that it needed to be stopped.

As for the huns, even though they have the reputation of having strict tradition that must be followed by their people, their leaders have the reputation of treating the people really well.

This make some romans happy when they are conquered by the Huns

Many people from the Roman empire believed that the Roman government was oppressive and that the taxation was over the top and that it needed to be stopped, which is something that the Germanic tribes would do.