It's more of an event for the chassidus, rather than just a wedding. In their eyes, it would be like limiting the amount of people in shul for simchas Torah. Additionally, it doesn't create any pressure for those who aren't rebbe's.
Better, still not fully satisfied, though.
In addition, and this may be hard to understand for non chassidim, this event is one of their only outlets of entertainment. (Even without Covid) most chasidim don't attend sporting events or movies. So these weddings something they really look forward to and are willing to make an exception for their rebbe.
I'm not justifying anything, only trying my best to explain. And having seen this argument play out elsewhere I know there will still be some or even many who begrudge these large scale weddings and I understand that.
I get that.
The Rebbe belongs to the chassidim, and therefore the Rebbe's simcha is not a personal one, but a communal one. Therefore, the wedding isn't a "wedding" per se, but is to be celebrated more in line with other yomei d'pagra, as a community event.
(Way outta my league here. Just taking shots in the dark.)
Yeah, ok. Somehow most Chassidim themselves seem to think of it as a Rebbella wanting to feel good about making a "good" shidduch. I guess it has *potential* to be a community event, but that depends on how *real* the Rebbe is.