“perhaps because the recent fast (in the case of Tu B’Av) ‘
By the 6th day after the fast, it is not so recent.
When the temple stood, the 9th of Av was not a fast day.
There are many sources besides “Tu B’Av” that show that the stringencies of modern day Chassidus were not the norm throughout the vast majority of our history.
Chassidus is not for everyone, and non-Chassidic paths of keeping Torah and Mitzvos must be available to any child who does not connect to Chassidus.