Of course binance maintenance was a cause for the market to lose 25 billion dollars.
Imagine if NASDAQ or Dow decided to just shut down for a day for "maintenance".
It would totally throw the entire stock market off.
Commodities, securities, stocks, and yes, crypto are affected by second to second trading decisions and price fluctuations.
When the vast majority of a coins trading volume comes from Binance and it suddenly stops.
It will have a huge impact on its price in other exchanges.

But, a smart trader can take advantage of this through arbitrage or by even simply buying back in.
Temporary setbacks are exactly that: temporary.
The market will rise again just as quickly as it fell.