Are we to believe that such fights would happen less if Disney were cheaper and thus (from some people’s perspective) better value for money? Crowds and the Florida heat are an unavoidable part of the experience, which leaves cost as the only real variable.
Your confusing instigators with root causes...
The instigators like heat, fiscal concerns, etc lead to STRESS
Pressure to meet goals or expectations lead to STRESS
Instigators like duration, heat, distances lead to FATIGUE
Frustration can arise from things like repetition, disappointment, etc
These factors combine and set people off. So root causes are more like Stress, Fatigue, sentiment.
Someone who is fatigued, but happy or satisfied is less likely to snap vs someone who is fatigued but also frustrated.
That's why it's talked about where the culmination of things can lead to people acting out, even if out of character. Extenuating factors like fatigue and stress can cause people to act out.
The primary thing that people are talking about is how the current Disney experience is leading to more stress. Factors like expense, scale, expectations, all create more pressure and stress on people.
Pressure and stress should not be things associated with VACATIONING. A concept Disney Parks has forgotten and instead created the idea that people should just buy their way out of the fear of missing out or lower experience. "Just buy these upsells so you don't have to worry about it.. " which in turn just creates more pressure for expectations and the potential for more stress due to the financial burden the experience now represents.
Coaching people to pay more to avoid problems creates higher expectations. So when you fail to meet those expectations (like long lines even though you paid for a line reducing feature) you have amplified the reactions people will get.
TLDR - Disney is contributing to the problem by failing expectations and then monetizing (and increasing people's burden->stress) the opportunity to improve it's experience.