I've recently heard that some rabbis are claiming that we no longer have to mourn the destruction of Jerusalem, because Israel now holds it. This is totally outrageous and shows a very superficial comprehension of what Jerusalem is to the Jewish People.
Jerusalem is not just a bit of real estate, the same way that the Tanach, Jewish Bible isn't a history book. The Tanach is a book of theology, and Jerusalem is Holy and meant to be the location of the Beit Hamikdash, Holy Temple.
Until the Jewish Israeli Government takes full sovereignty over Har Habayit, the Temple Mount and begins building the Third Temple for traditional Jewish Worship, we must mourn the destruction of our ancient Jewish Kingdom and Temple.
According to the attitude of those rabbis, they may as well read the Torah in synagogue from a paper book and not from the special parchment.