What now? Am I hallucinating? Maybe I am a liar?
Maybe you should play your own mod from time to time, to see what is possible and what is not.
I only wish I could play it more, dear. Playing and watching LPs takes a serious chunk of my free time as it already is. It also takes away from modding time.
Not calling you a liar, but hallucinations are quite common around here, due to all the RNG and other nontransparent circumstances involved. And some go an extra step and proceed to jump to conclusions that I somehow stealthily changed something (and in some rare cases, apparently just to personally spite a player). I deal with crazies daily, and no wonder, we're all crazies here...
As for the real reason, it seems Meridian already found it. These tiles have 100 armor. If OXC changed the terrain damage formula, they'd be much harder to damage. What are the chances, tho, that I've been doing the exact same thing as you did (namely digging in alien base) just mere weeks after the version came out? In a game that requires avg. 500 hours to fully play through? Get real. (Actually I never tried digging in alien bases, neither in vanilla nor piratez... seems comletely pointless but I don't judge...)
Also I concur that the terrain seemed somehow... too malleable, compared to vanilla... Good thing it was fixed, although some terrains, like the bank, will probably have to be rebalanced to allow hammers/pickaxes.
Sorry for the big post, but these things needed to be straightened out.