The difference in electronegativity between oxygen (3.4) and hydrogen (2.2) is greater than it is for sulfur (2.5) and hydrogen (2.2), which leads to stronger intermolecular forces (hydrogen bonds) and therefore more energy (heat) is required to break these interactions.

So people should work for free? Do you understand how much time and work Dr. Ashenhurst put into making his summary sheets? Drawing the reaction mechanisms and other diagrams takes a lot of time, and also requires software that costs a great deal (i.e. MarvinSketch), then making sure that all of the information is not only easily understood, but also factually correct. You’re right, knowledge cannot be bought; what can be bought though are services that make the acquisition of knowledge easier. If you want to trawl through organic chemistry textbooks sorting and picking the relevant details from complex and highly specialised details then go ahead, but many people take organic chemistry because it’s required for something else and just need to understand the fundamentals. We only get so much time as humans, and whilst I’d love to learn everything I can about every subject that fascinates me, it’s not at all realistic. Grow up.

Have you tried making a giant reaction map for organic compounds at any point? I’m aware such a thing would inevitably look insanely complicated, but it’s still something I’d quite like to see!