In organic chemistry, there’s a concept called delocalized pi orbitals. The exact reason why it works is complicated and outside the scope of organic chemistry, so I’m not sure if I can really explain it anyways. But the takeaway is that when you see a double bond, single bond, double bond pattern, that generally indicates that the bonds are actually being shared across the entire motif. ie, it’s not really a double bond, it’s more like… a 1.5-bond.

Having the bonds be shared across multiple atoms gives that region of the molecule special properties, the primary of which is that it tends to be really stable. The reason for that is that any disruption toward that region (eg, adding an electron) gets distributed across the motif, so that each atom is only minorly disturbed.

And the bigger the motif is, the more stable the region is because it’s able to distribute disturbances better.

Benzene (the hexagon motif circled) is made exclusively of this double bond, single bond, double bond motif. And as a result, it’s well known for being extremely difficult to modify or destroy. You really have to jump through hoops to do any sort of organic chemistry with benzenes. The motif circled in testosterone still has delocalized pi orbitals, but it’s not as extensive as a benzene, and so it’s less stable