Two guys walk into the enemy base.
"Plant bomb here", says the objective wheel.
Guy1- Hey, what are you doing? This here is my objective!
Guy2- Nuh uh! Its my objective, and her name is- Kerbluh! *Both die from a lone camper inside the base*
-Teamwork is about sacrifice. I will have to sacrifice my "Bomb" so that you can score the big points? Where is the fun in that?!

Achievements:
I was looking at the achies a while ago and noticed most would be earned in multiplayer. I don't always like playing pvp, but I love achies. Can I turn bots on and still earn multiplayer achies?! Its all the same, right?

If someone else beats you to the punch of performing an objective, you can always provide him covering fire. You get XP bonuses for kills you make near an objective and for being around someone who's performing an objective.

^^This^^

2 Soldiers show up together, first one sets bomb, while second covers him. Then the one who did the objective gives him ammo. Both gain XP for being there, and the guy killing enemies gains XP bonuses on each kill for defending the guy completing the objective.

Yeah, I guess that'll be okay...

But what about my achievements?!

You'll get achievements for defending people performing objectives as well, if there are any for performing the objective yourself.

For me fun doesn''t come from the XP you get but from the things you share with others. Like completing an objective, it shouldn't matter if you're the one planting the bomb or covering someone's ass.
That's what I believe.

If you're so eager, get it while playing with bots.

I shouldn't have used "Fun" in my scenario...I just don't want this to be the case everytime I choose that objective in the wheel. I do like xp...but its not the most important thing...

If you dont want to play online, dont. But dont complain because someone stole your objective. That Will happen much less offline with bots, and you can change your objective to assist your team if it was already taken anyways.