Yea, I noticed this. It is 110% easier to defend an objective than to take a new one, and yet almost 99% of players spend the entirety of their gametime trying to rush in and take a new objective. Almost no one sits on, or nearby an objective to prevent its capture by the enemy.
I think it's more that the game is currently set up to heavily reward captures (points and you respawn your team) So. This reinforces a gameplay loop where the players that rush in and die over and over usually end up coercing their smarter, more cautious teammates into doing the same through various approaches. (most involve using the microphone to bitch and moan and complain about "campers" and "don't be a pussy".
So other than the built-in incentive to respawn your team, you also have the social pressure to "not be a pussy" and "revive us dood" from your team the entire game. After a few games where that happens players just learn to EXPECT their team to expect them to rush after capturing objectives.
The cautious gameplay is eventually conditioned out for the most part. I wouldn't say this is due to there not being score points allocated to the task. I'd say it's more of the MASSIVE incentive to capture a new point because that's the only way your team gets respawns....
Perhaps there should definitely be a "Capture denied" or "killed enemy near owned objective" point bonus.