I have no issues with erections or seeing erections that happen naturally, they are normal and natural. I also believe that erections that occur by themselves need not and should not be hidden as if they are disgraceful. The problem arises when some men deliberately cause erections to get some sexual thrill by showing them off or start touching themselves in inappropriate ways. I also understand that on a site like this once photos of erections is allowed the site becomes inundated with erections photos because men are proud of their erections and before long there would be so many erection photos here that it might as well be called a porn site.
In most cases unless you are a hormone raging teenager erections should be a fairly rare and and of short duration if they are of non sexual origin.