PC, despite Windows being the OS of choice is still very much considered a neutral zone due to the open nature (currently) of it. Sony gives devs a bit more leeway while still saying they cannot directly support their competitor (The Xbox), and for games published by them (such as Helldivers), they can still make some money off the top as a result. PC is also seen as more complicated to get set-up and running, so the convenience factor of a console means Sony isn't all that scared of PC stealing their potential market-share, they're more scared of a direct competitor in the form of Xbox.
That is not even remotely true. Sony is much more likely to lose a gamer to the PC than Xbox. It happened a lot at the end of last generation. It is one of the reasons behind the NEO. If Sony was worried about losing gamers they would shut off any cross platform especially with PC. This is all about the bad Sony we have seen since launch where they have done a 180 on the 4thegamers mantra.