There are Gedoilim whose opinions are constantly quoted by Yeshivishe Litvaks who embrace the anti-Zionist SHIT'ah since it suits them better not to join the army and defend their families; ... some of those Gedoilim quoted by them are of the bizarre and outrageous opinion that the open miracles we all witnessed during the 6 day war ....were performed by Satan!
But thankfully, there are Gedoilim who constitute the silent majority and who are of the opinion that "Yom Yerushalyim" is a Yom Tov that should be embraced and celebrated and some even are of the opinion that one should recite Hallel with a bracha!
I compiled a sampling of those Gedoilim!
According to Harav Avadia Yosef, Harav Yitzchok Kaduri and Harav Ben-Zion Abba Shaul, one shouldn't say Tachanun on Yom Yershalyim
see: הרב יהודה ברכה, שו"ת ברכת יהודה, ח"ד סימן טו'
Note that all the Gedoilim mention the great "miracles" on that day ....
From the Tzitz Eliezer, Harav Eliezer Waldenberg: