The problem with the latter sequence (FOLFOX bevacizumab, irinotecan or FOLFIRI, irinotecan plus cetuximab) is that, at least according to RCTs, FOLFIRI is probably inferior to FOLFOX in the second-line setting. Based on the relatively poor performance of FOLFIRI second line, and the fact that FOLFIRI and FOLFOX are equivalent first line (aside from toxicities), I would argue that FOLFIRI should go first.
Anyway, I am sure that Saltz has valid clinical reasons for FOLFOX plus bevacizumab first line. We just don't have the RCT to support it yet. I would like to see a FOLFOX plus bevacizumab vs FOLFIRI plus bevacizumab trial. Then we could all stop arguing!