This context is not very relevant in Jewish life today, where religion is centered on family and community, not the Temple sacrificial rituals of ages past. Therefore, the observance has fallen out of fashion by most non-Orthodox Jews. Some, however, have taken a bit of Midrash about Tisha B'Av to create a new context, one that is relevant not only to Jews, but to all humanity, and especially today.
Why was the First Temple destroyed? Because of three [evil] things which prevailed there: idolatry, and immorality, and bloodshed... But why was the Second Temple destroyed, seeing that in its time they were occupying themselves with Torah, [observance of mitzvot, and the practice of charity]? Because therein prevailed hatred without cause. That teaches you that groundless hatred is considered as of equal gravity to three sins, idolatry, immorality, and bloodshed, together. (Talmud Bavli Yoma 9b)Is this not what we see today? Certainly, there are many people doing terrible things! Wars, crime, and exploitation of the poor and the weak (from institutional discrimination to police brutality to pedophilia) abound. In our personal lives, there is conflict and suffering.
However, the message of Tisha B'Av is that these phenomena are only one half of the equation. Our world is not broken simply because bad things happen. Our reactions to them are just as important. Too often our natural reaction is to point fingers and look for someone to blame our (or the world's) woes on. How much easier to hate than to seek constructive solutions and self-improvement! Whether we place the blame on liberals or conservatives, on those more religious than ourselves or more secular, hateful blame is surely anathema to the goals we claim to espouse.
Baseless hatred of oneself (guilt/shame) is no better, as it disempowers the individual from taking positive actions. These positive actions usually do not give the emotional high of self-righteous anger or anguish. They are usually mundane actions of doing what needs to be done in spite of our feelings, of showing love and kindness to those who are not reciprocating it, because it is the right thing to do.
Many if not most Jews observe Yom Kippur in some fashion. Saying sorry and "atoning for our sins" is a cleansing feeling. Clearing the slate for the new year is energizing and motivating. I would love to see Tisha B'Av take a similar place in modern Jewish life. The Haftorah cycle recognizes the connection between these two fasts with the Seven Shabbatot of Consolation. How much more powerful would our capacity to forgive and seek forgiveness be if we spent the next two months actively tuning in to how we can turn our hatred into love?
