You fight to protect yourself and your loved ones.
Well, squirrels do that. It's a part of us as humans, certainly, but I'd like to think there's a lot more to us than that.
And even then, love is definitely part of the motivations involved, as Amaris posted.
It was like every female crew member decided to eat with him. If he wasn't so good looking, would they have? I'd like to say yes, but I know better...
How did this idea emerge that Tyler is good looking?

Did I miss a memo that being a lanky greasy-haired guy with no chin and a neckbeard is the current hot look? If so, I had a few friends in high school whose main problem was being way ahead of their time...
I believe that the best way of dealing with our darker nature is to first admit that it exists. ... History has shown us that we are capable of great evil, and not just our leaders, ordinary people as well...
Okay, I can agree with that...
What Discovery is presenting us with is a situation that is an existential threat to the human race.
On the other hand, I can't agree with that, not by a long shot. Nothing DSC has shown us or told us about the Klingon war suggests it's anywhere near that dire.
You see I'm the type of guy who believes that everything can be made right if people would just sit down and talk to each other.
And once again, I can agree with that...
So presenting an enemy who can't be reasoned with challenges the way I think.
Here's where you lose me. Fiction is actually depressingly full of enemies who are depicted as implacable, inhuman, ruthless, and immune to reason. Just drop by the Star Wars universe and check out the Empire/First Order. (Real-world politics likes to pretend that enemies are that way, as well.) What has always set Trek apart is its willingness to
defy that tired trope and show that diplomacy actually can and does work.
Ardana is a Federation member world. Plasus routinely uses torture to get information from prisoners; and still routinely executes criminals.
Not exactly TOS at its best... but yes, undeniably, that is a canonical example of what you're talking about.
However....
The Federation knows all the above; yet because they allow each member world to govern it's society as the leaders see fit - the Federation Council and member worlds have no issues with it...
This part is far from clear. The episode suggests that Ardana's rigid caste structure was unknown to Kirk and Spock when they arrived (thus, presumably, absent from Starfleet and UFP databases). How the planet could have acquired membership while keeping such things secret is an unexplored issue (but then, it's only one of many issues the episode fails to explore).
(And no the above ISN'T the only example I can give from the TOS era - but I don't feel like doing a longer post, this example proves the point I was making.)
Well, I don't know about that.
This page from Memory Alpha leaves me thinking that Ardana may in fact be the only such example from the TOS era...
...and moreover, it really doesn't prove the larger point. I'll stipulate that it shows not every Federation member world in the 23rd century necessarily lived up to its high ideals. (Similarly, in the US today, we still have states like Alabama.) That's different from saying those ideals weren't present, or that the future depicted in TOS was not, by and large, one of utopian idealism.