Rashi explains that the list of places in the first pasuk in our parsha all are allusions to sins done in the midbar which Moshe was giving tochacha for. "Chatzeiros" alludes to the episode of Miriam's lashon ha'ra which the meraglim should have learned from but didn't.
Mizrachi asks: Rashi comments that "Paran," mentioned earlier in the pasuk, alludes to the cheit hameraglim. Why do we need two allusions -- Chatzeiros and Paran -- as tochacha for this same sin of the meraglim?
Maharal in Gur Aryeh answers (see Mizrachi for a different answer) that there are two different aspects to the meraglim episode, each of which independently is deserving of tochacha. The first sin was the act of sending the spies, which demonstrated a lack of emunah -- Paran. The second sin was the failure to take heed and learn from the example of Miriam -- Chatzeiros. It's one thing to do wrong, but it's a far worse thing to do wrong when one should have known better. The failure to learn a lesson is itself a crime.
The Sefas Emes writes that the tragedy of churban bayis sheni is more serious than churban bayis rishon (compare the 2000 years we have been in galus with the mere 70 years of galus between bayis rishon and bayis sheni) because before churban bayis rishon the people could perhaps have rationalized dismissing all the warning and nevuos -- they really believed the Mikdash would never be destroyed. Yirmiyahu (7:4) quotes the false prophets who told the people, "Heichal Hashem, Heichal Hashem, Heichal Hashem!" This is G-d's house -- nothing can happen to it. Later, as Radak explains, Yirmiyahu (22:29)echoes back to them, "Eretz Eretz Eretz shim'i dvar Hashem..." that destruction will indeed come. (BTW, there is one more pasuk in Tanach where you have a refrain repeated three times -- I'll leave it to you to figure out where it is.) In the days of bayis sheni, those rationalizations could not hold water any more. Once you see that the Mikdash can be destroyed, then you have no excuse not to think that it can happen again. More than that -- failure to learn from what happened only compounds the sin the second time around.