Well, you can blame the likes of Slothfield who started spruiking it after MNF was canned from 2017 as a result of Dave Smith's decision to award Ch9 regular Thursday night matches. This was simply nothing other than News Ltd chucking a dummy spit and their way of screwing the fans over (which they've been doing since the SL-war) in retaliation for losing MNF.
As I've already said, it's not only that Friday 6pm is one of the worst ideas in the history of rugby league broadcasting in this country, but furthermore WHO in the ARLC and WHY did the ARLC agreed to this proposal from News Ltd is a mystery. As the expression goes, it takes two to tango. I thought the purpose of the ARLC/independent commission was to sort these issues out, and that "the fans were going to have their game back" (as the likes of Gus Gould were saying at the time a few years ago). The performance of the ARLC since Smith left has been very disappointing, and appears to be nothing other than News Ltd back in control of the game, just under a different guise (whilst at the same time giving the illusion that the game is independent of their control). And I do question the timing and appointment of Greenburg as CEO, but that's a topic for a different thread.
Sunday 6/6:30pm was the most logical timeslot to replace the MNF game with if the ARLC still had this obsession with not wanting games to overlap with each other on the fear it was going to devalue the tv rights deal (which is complete utter nonsense, as AFL/EPL/NFL and other sporting codes with $1+ billion tv rights deals still have matches where the timeslots overlap and are still extracting good tv rights deals, whilst at the same time maintaining a good % of matches in family-friendly timeslots).
Furthermore, the 6pm game pushes the Ch9 Friday night game kickoff back to at least 8:10pm (ensuring they have enough time for a pre-game show and to give the 6pm game broadcast enough time in the case of golden point/on-field delays such as injuries and constant video ref decisions), finishing close to 10pm and most people at the game getting home after 11pm on a Friday night. So, now you have two timeslots on Friday that are not convenient for people to attend: 6pm for people who work, and 8:10-15pm for families with younger children and parents. In this situation, the ARLC would've been far better going back to 2 Friday night matches at 7:45-50pm kickoff.