He wasn't into barbecues or bitul Torah, but he encouraged Jews to hang out a big American flag.
It can be confusing because on one hand, we are supposed to firmly entrench ourselves within our own Torah culture & value system, maintaining a healthy separation from anything not part of Judaism—no matter how appealing.
On the other hand, we also need to appreciate the great gifts Hashem has given us.
American Jews have been allowed to flourish in America.
Torah communities & yeshivot have flourished in America.
Even with the Jew-hatred that exits (and has recently increased), it's still not comparable to the Jew-hatred that existed as both the cultural & institutionalized norm in other societies throughout history.
Here's a snippet of what Rav Miller said:
Today, when so many meshugaim are trying to desecrate the American flag, and when the wicked courts and the wicked Supreme Court have sanctioned the desecration of the flag by ruling that burning the flag is not a crime anymore, so we have to show that we appreciate Hashem’s gift to us.
America is a great gift and I say that every Jew today should hang out a flag on the 4th of July.
Even if it’s just li’hachis, just to show the liberals, to show the resha’im that we do appreciate America!
You have to know that the liberals and the leftists are ruining America.
They are wicked people and wickedness has no calculations.
They do things only because of wickedness, and therefore we should do the opposite.
They want to destroy the moral fabric of America and the least we can do is show that we appreciate the great gift of America.
I say that we should hang out the flag; no question about it.
TAPE #792 (1990)
After all, America is a good country.
We came from countries where we were persecuted, and this country gave us all the rights. I would say we should kiss the ground of America.
I was in Europe for some time; I went to study in the yeshiva in Slobodka.
And when came back, I saw even more that this was a blessed country; it’s a gift from Hashem to us.
Tape #833, July 1991
The American flag is a sign of decency and compassion. That’s what it is.
Of course, it’s only a symbol, but it’s a symbol of what Hakodosh Boruch Hu is doing to us.
America is a great gift to us from Hakodosh Boruch Hu.
And therefore it’s not America that we have to love; we have to love Hashem who gave us America!
And if Hakodosh Boruch Hu gives you Australia, then you have to love Hakodosh Boruch Hu who is giving you Australia.
And so all of us should be grateful to America.
But it’s not America – it’s Hashem who gave the gift to us.
So let’s try to maintain that gift and make sure that the liberals don’t ruin it.
TAPE # 701 (July 1988)