Mock Draft ignores WR?

New here, haven’t read much. Got a question as I try to figure out how the analytics work.

Our league is
RB x2
WR x 2
RB/WR Flex x 2
WR/TE Flex
no TE/K
0.5 ppr

When I mock draft and take 4 straight RBs, I get 97s and 98s even if I’m starting WR 3s and WR4s for my 3 WR spots. FOr example, I took 6 straight RBs, then a QB, then ended up with Boyd, LaViska, and Mike Williams as my 3 starting WRs. Got a 98 on that draft.

Seems like even if I take a WR with one of my top 4 rounds that is projected even 30-40 points above that RB, and I end up with a RB later that doesn’t change that math, it still ranks my team as weaker. By all accounts, drafting any WR over any RB in the top 4 rounds weakens my team.

Is this a flaw with other types of leagues, or is our ability to play 4 RBs not conducive to this algorithm? Or is that really the way to go for the strongest team?