As much as we like to think that, it's not the case. It was purely on ability, particularly the lack of quality in forward play. You've got to remember that England expect to dominate 90% of the games they play so a full back's attacking impact is considered to be as important as their defending.
If Thiago scores 20+ goals the next few seasons, picking players like Richarlison is going to look totally bonkers. Really speaks to the weird establishment mindsets of
some fans/organisations that a degree of their thinking isn't "will this help us win?" instead "how will this look?" and probably contributes a lot to why they've not won a world cup in 20 years despite being the self-crowned kings of football. I hope Southgate didn't have that mindset, but who knows what goes on subconsiously.
At the end of the day, every fan wants to see their team's players representing their country, you can tell by the comments underneath every England squad announcement.
Palace, Everton, Bournemouth, Forest, Brighton, Brentford fans... all apparently have an incredible unsung player that didn't get picked because their club isn't sexy enough. A lot of the time the reason is probably because the manager thinks there's someone better, or they don't fit into their playing style or whatever.
With Rico I think this was probably the case. His attacking output has always been the weakest part of his game, and next to players like Hickey and even KLP he doesn't look as "natural" a footballer. I think a lot on here have very rose-tinted goggles when it comes to Rico -- I suggested he wasn't in the top 20 left backs in europe on here a while back, which of course went down like a lead balloon.