Well, the "pussy-like" comment was derived from that, from the limited MGS stories I've read so far, they're not afraid to use very strong themes and messages (real-life war, child killing, torture, etc.) which I don't see a lot in western games (which is normal because Japs are crazy in storywriting). Deus Ex and other western games set in the modern or near-future world may have discussions over war or cruel acts, but they're never too explicit and are mostly pretty tame in background story writing (which is once again normal since western society loves to bitch anything in video games from religion to references of real war to child killing).
Not necessary DX and other games (never played Splinter Cell before) have shitty plots or something, but for me it's pretty refreshing reading MGS's more brutal and dark stories (and, well, depending on your view, cartoonish), as the darkest stuff I've tasted on PC (in which 99% are western games) so far is only Witcher grade.