This was because Washington, who was elected President via a democratic process, did not mandate the tax by fiat without regards to opposition, which is what a fascist government would be able to do. Rather, Alexander Hamilton recommended the whiskey tax to Congress to help pay down the federal debt the U.S. incurred for the Revolutionary War. The House of Representatives and the Senate, both democratically elected chambers of the legislature, debated the measure, wrote bills, passed a bill in both houses, compromised the bills between the two chambers, wrote a final single bill, passed a vote in both houses on that, and presented it to George Washington, who signed it into law.
The rebels shouted that they were suffering taxation without representation; that is untrue - they were being taxed with the people being represented via the House of Representatives and the states being represented via the Senate. Therefore, they were not suffering tyranny like they did under the British Empire, in which Parliament did not allow the colonies any representation in the House of Commons nor the House of Lords.