τούτους οὔτε μελετᾶν τῶν ἐλευθερίων πόνων οὐδένα παρώρμα οὔθ᾽ ὅπλα κεκτῆσθαι ἐπέτρεπεν:
why perf inf and how it would be different if the pres inf κτάομαι were used here?
It’s the usual difference between perfect and present. κεκτῆσθαι is to possess, to be in possession of, whlle κτᾶσθαι is to acquire, to come into possession of.