Whoever the douchebag was who was opposing base raping as a BA and killing new players as they spawn ought to be mighty ashamed of their actions. Hopefully Iron__Eagle understands that there are jackasses everywhere and give the game another shot, but it's entirely possible he continued with his proclaimed course of uninstalling.
So, that was awesome whomever, give yourself a mighty good pat on the back for that one.
I haven't been playing recently, so it wasn't me. But uh... depends on the base. If it's a capturable base, there's nothing wrong with that. Why should a BA wait for you to buy and get into that Huit Prime, Rifleman, or Black Lanner with 6 MGuns so you can easily kill him? I guess if he somehow manages to almost kill you, he should wait while you make repairs and power up again...? Nobody thinks twice about spawn-killing a BA who is still buying weapons in a BA bunker (and there are no more loadouts, so it's gonna happen), so why should a BA let mechs and vehicles ready up and train their reticules on him behind walls for him to peek out?
Now if it was the primary spawn, and it wasn't a map where the primary spawn is capturable, and he is inside the spawn area killing you, sure it might be right to get mad at it (although at some point, everyone HAS to try it once, if only for a few minutes). If he kills you with his mpPPC from outside the base defenses as you are getting into your mech, that's just too funny and 1337 to be mad at. Trust me.
Keep in mind that this strategy is super-easy to defend against. A BA can only carry 5 Inferno Charges, and after that he'll have to run back to an APC or another base. And if you know he's there, just immediately run after spawning to get him to whiff on his Inferno Charge/laser. YOU can buy Inferno Charges, then. And everyone spawns with the best BA-killing weapon, so you could always just... you know... shoot him.