If you are not meant to be able to take over the other factions bases and PVP in them, Bioware needs to up the defenses of the bases and unflag people for PVP as soon as they enter the bases. In terms of the spawn camping or camping of medcenters is concerned this once again is Bioware's screw up. BTW I'm not saying the OP was spawn camping, he has said he wasn't and I'll take him at his word on that unless someone can prove otherwise. Players on PVP servers should be given an option to respawn on the fleet or their ship, or make quick travel an instant ability so it can't interrupted, there are so many ways Bioware can fix the spawn camping issue. Spawn camping can be a problem but I don't blame the players that are doing it, I more blame Bioware's bad design decisions for it happening.
A side story, several months ago a friend and I, on our Imps, went on a little adventure to see how many Republic cantinas we could get inside of and visit. We expected it to actually be a challenge getting into them, we were surprised to realize it was extremely easy just with the two of us to get anywhere we wanted and neither of us were stealth classes. The conclusion we came to was either BW designed it so taking over the other faction's bases was intended or if such things were not intended BW had completely failed at designing real defenses for these bases.