Seb,
I completely understand what You say and as I have written final decision is upon every single at the end. As MD I have obligation to say everything I know. Biologics are in use for short period of time that we may give solid conclusions. Unfortunately even for such short period of time they showed very bad side effects. There are people on this forum also who experienced that. When I say something like this I don't even think on pneumonia but MS, cancers...
Also I guess there are young people who want to have children, and there are no data what side effects biologics may cause to babies and genetic material of parents.
Maybe biologics will show as revolutionary cure for AS but in this moment it is far too early that anyone may say "take it, it is the solution for you"