It could definitely be a 'personal viewpoint' thing. Picard was somebody with a strong interest in archeology and the study of things, so on some level his leanings were more scientific. On the other hand, the crowning moment of his career (the Battle of Maxia) was one where he outwitted and defeated an enemy ship in combat, and had a tactical maneuver named after him. He's indisputably a military officer of some considerable measure, but he simply prefers the analytical approach.
Kirk was seemingly trained as a soldier. Although his Starfleet wasn't any
less inclined towards diplomacy than Picard's, it would seem the emphasis was skewed more towards at least the possibilities of war, and Kirk's generation had a harder edge. One might reasonably describe their outlooks as the difference between a 'peace time' and 'war time' military. Picard had seen combat in his past, and was evidently just as accomplished a soldier as Kirk, but on a
personal level it didn't tally with his beliefs or interests, so he used every opportunity to downplay Starfleet's military side when asked about it, citing as evidence the fact that Starfleet hadn't engaged in large scale combat for many years, and that the organisations own mission statement emphasized exploration and discovery over simple territorial imperitives.
People mention "the speech" from
TNG: Peak Performance, but what they fail to recognise is that the context of the entire premise of that episode is based around the idea that Starfleet is engaging in the war game exercise because they recognise that they need to harden up their training regime again in advance of the impending Borg threat. Perhaps the introduction of more formal uniforms the following year was also a part of this concerted move to, as it were, 'turn the tide' of thinking for a generation of officers who were not necessarily as militarily minded to begin with (the occasional graduate or NCO who'd seen battle with Cardassians aside.

)