Not music to their ears
Although they have no access to rehearsal rooms, many of the elderly have obviously developed a feeling similar to that embodied by professionals, ie, the satisfaction of showing off their talents and joy in front of a live audience. They may act nonchalant, but they crave for a level of showmanship complete with costumes and the whole nine yards. Applause or not, it is a stage they did not get a chance to grace during their youth and are now making up for it.
That probably explains the volume of the music, which is usually loud and has now set off a cross-cultural skirmish. Parks in China are generally located far away from residential areas. If a residential building can hear the music, there are probably all kinds of noises that either drown out the music or blur it into the ambience. In China, this kind of dance music is by far not the most annoying.
But not in New York, where one culture's mellifluence could be another's stridency. Chinese music, especially that used for the drum dance, does not easily merge into the background. It catches attention simply by its exoticism. Coupled with the high volume, it may well incite unpleasant responses from neighbors who do not share the culture. This is somewhat equivalent to a classical music aficionado and a heavy metal lover engaging in a debate about which style sounds better. Each side is convinced of the superiority of the one he prefers.
Even though the press report did not mention it, I'm pretty sure the dancing ladies felt unappreciated for their efforts to entertain the neighborhood. Sure, they would claim it was for self-entertainment, but in the depth of their hearts they wanted to impart their joy to those around them. Not in a thousand years did it occur to them to disturb the peace of the environment.
If enough people take part in the activity, I assume they could apply for the free use of community centers where rooms are sound-proof and air-conditioned. The US has much better public service facilities at the grassroots level than China does, so people who settle there, including Chinese migrants, should learn to fit in that mode of operation. If the group qualifies as one of performance, it may even be eligible for partial government funding. Of course, economic difficulties in the US have led to large cutbacks and financial support for such groups is not as easy to obtain as before.