Question

Last night, at dusk, a few minutes before the fast ended, I was walking through Kikar HaMedina in Tel Aviv. Around me were many people walking because there was a protest there against the dismissal of the Attorney General.
I spoke with a few protesters; it was interesting and varied, and to my surprise several told me they were fasting on Tisha B’Av… They did not look religious, and at least two explicitly said so.

I left there, and until now I still can’t understand it. Maybe the Rabbi knows an explanation?
Why would secular people fast on Tisha B’Av?
Yom Kippur, fine — that’s rooted deep in the Jewish soul and tradition.
But Tisha B’Av?
In exile, fine, but now we’re in the land of our forefathers; in the end there’s no sense of exile and persecution, and they’re not religious people who are, by definition, obligated by Jewish law.
You could dismiss it by saying they were just bluffing me, but I don’t think so — they seemed to be telling the truth.
 
Does the Rabbi know the explanation?