This might seem to be a stupid question but does an obelisk really represent an erect penis?
Only to Sigmund Freud, or to an extremely sexually frustrated person with a penis fixation!
Seriously, they were monuments erected for various symbolic reasons. The quasi-phallic shape may have been intentional, or may have been accidental, the intent being to establish a “landmark” point by a tall, slender structure.
Yes, sometimes an obelisk is just an obelisk.