While a lot of Belgian beers can be quite on the sweet side, there are some sides to this.
With such a tiny country having 180+ breweries making perhaps around 1200-1500 different beers one can't really claim them all to be sweet. The range of totally different types of beer in Belgium can not be beaten anywhere else on earth.
You try 500 of their brews, and will still find several new tastes afterwards that you didn't think existed.
That's why Belgian beer is such great fun!
Initially, they often range between 6-9% in alcohol which balances the sweetness to an extent. The idea is to have a lot of everything in the beer (although bitterness is historically not a Belgian thing).
The newer micro breweries in Belgium started to add a lot of hops the last two years or so. Some of them even started using American hops that contains higher amounts of alpha acids. Traditionally speaking, Belgian beers used local hops that are very low on alpha acids, and they use much more aroma hops than bittering hops.
So today you can find lots of beers from Belgium that are heavy on the bittering hops, some are even dry hopped. And this has also turned out to be the trend for this year, so more and more beers are turning out drier and bitter.
Some examples regarding drier Belgian beers that are not at all sweet but instead hoppy:
La Rulles Esteval
La Rulles Triple
De Ranke XX Bitter
De Ranke Guldenberg
Orval
Chimay Triple
Westmalle Triple
Duvel
Duvel Tripel Hop
Gandavum Dry Hopping
Saison IV
Poperings Hommelbier
Slaapmutske Dry Hopped Lager
Arabier
Dulle Teve
Cheers!