I have to disagree here. Fermentation temperatures and yeast strains do, of course, have a huge impact on the final outcome, including, but not limited to, the effect of esters. It is not true, however, that all ales smell fruity. With the large variety of top fermenting "ale" yeasts available, as well as some control to be exercised over the fermentation process, it's perfectly possible to get quite a clean fermentation. Kolsch is fermented with an ale yeast, for example.