Which other game has the feature ping kick? 
Battlefield series, Call of Duty series, King Arthur's Gold, Altitude, Counter-Strike Source, Half-Life 2, Team Fortress 2, and those are just the ones that I actually played...
1) I notice absolutely no difference between when I play with bots on my computer and when I play online. If there's 0 lag for me, everything's happening super fast, in real time, how can there be lag for anyone or others whose ping is better than mine?
Lag spikes are another possibility. Sometimes it may seem normal, but then your ping might spike to a very high value which could cause you to get kicked. Also, I'm not sure why it happens, but sometimes it may seem normal on your screen but other players see you warp all over the place.
2) How much data do you think soldat has to transfer? Its not a graphic intensive game like WOW that has to transfer like 500 kb a minute. It probably only transfers 10 kb a minute. Even dial up is good enough for that. 300-400 ping is more than enough for this!!!
Denacke has explained the difference between ping and bandwidth pretty well, so
read his post. I'll also add that Soldat has a crappy netcode, so while other games might not be too laggy even with a 200 ping, Soldat suffers a lot more from it. Also.. "graphic intensity" has absolutely nothing to do with internet connection. WoW is aclually a lot more forgiving in terms of lag than Soldat, because WoW doesn't require as much accuracy and precision during gameplay.
3) I play other games all the time on game ranger which are far more resource heavy than soldat, and there's no lag for anyone there either.
It's possible that your router doesn't like something about the way Soldat sends and receives data over the internet. Try doing the things that others have already suggested. I would also suggest you download a previous version of the game (v1.5) and try joining any of its servers (if there are any left), try turning off your firewall and check if there's anything wrong with your router.
I'm a programmer so I know what I'm talking about.
Your "2)" creates a completely opposite impression...
