The author does not understand that unscientific convenience surveys of men who attended sex clubs are not, in fact, representative of the wider gay population. For example, he makes claims like "this percentage of gay men said they had this many partners", yet it will be from a survey of men who attended bathhouses. Generalizations like this are very unscientific. He also has a hard time properly citing things.
An intelligent author might use the Laumann study (1994), The General Social Survey (2000-2018), the NATSAL (UK), and the Australian Survey of Sex which ALL show gay men typically have 10-20 sexual partners in their lifetime. About half report 0 or 1 in the previous year. The fact that this author just ignores other studies from the 80's and 90's which showed gay men did not on average have "hundreds of partners" is shocking. I know only the first study was available to him at the time, but segments from this book are copied and pasted all over the internet as "proof" of gay people apparently being awful sex addicts when in reality its about 10% of gay men who have more than 100 partners in their life.
This kind of cherry picking is something I have noticed in many books which aim to profit off misconceptions about gay people. This book is somewhat of an interesting insight into the subgroup among whom AIDS first effected, but none the less full of anecdotes and other pseudoscientific nonsense.