I think that there was something missing from the lesson if the facts are as reported - choice.
I assume that your instructor knew the conditions to be safe and within his own capabilities, then it should be up to the student wether to go or not. The student can only make that decision with a good brief on what to expect.
If the instructor considered that the conditions were safe but that the student may not like them, or may not learn what he was expecting to learn, then I think it vitally important to give the student all the information he needs to make his own decision. This means fully briefing the student on what to expect and what he may and may not get out of the lesson. After that it's the student's money and his choice. Looks like you didn't have that information with which to make the decision.
Of course, this all assumes that the conditions are known to be within the instructor's and aeroplane's ability - if not, or if it's unclear, then it's an absolute no-brainer.
By the way, it's not clear wether you thought that the lesson was valuable - what did you make of it?