I was (and remain) a huge fan of ST:TOS. That said, i fail to see the series as depicting a utopia. Despite the international (and outernational) cast, the setting is one of typical European-style exploration/colonization, with armed crews aboard heavily armed ships imposing their will on those subjects who's culture is deemed to be inferior (on numerous occasions, Kirk acted against the Prime Directive that purportedly protected against this). Hostility (typically promulgated by nefarious aliens, but also arising from unintended actions, primitive Vulcan rights, etc.) is depicted far more often than peaceful coexistence (presumably to advance compelling story lines).
Admittedly, the series lacked the dystopian elements that disturbingly have predominated in science fiction movies for the past 50 years (have always wondered about that - presumably ushered in by the cold-war nuclear era?)...
...which is why, according to The Guardian, "one of the fastest-growing cosmetic procedures in the UK is repairing stretched earlobes" (http://www.theguardian.com/lifeandstyle/2014/oct/19/cosmetic-surgeons-repair-stretched-earlobes).
When the existing treaty was drafted nearly 50 years ago, space flight was still in its infancy, and realistic scenarios envisioned today hadn't yet been dreamed of. Perhaps it's time to revise the existing treaty, or negotiate a new one?
...going to RETURN TO breaking into your homes...
"'Tis true, 'tis pity, and pity 'tis 'tis true." -- Poloniouius, in Willie the Shake's _Hamlet, Prince of Darkness_