Brachos 14 – ברכות יד

Tosfos points out that the allowance to taste food without swallowing is limited to a taanis yachid (personally enacted fast) but is not permitted during a taanis tzibbur (a public fast).  If we see that tasting doesn’t require a bracha then obviously it doesn’t constitute eating, if so why is it forbidden on a taanis tzibbur more than by a taanis yachid?