Massive plot hole surrounding Shepard and Cerberus

As we all know, in ME3 at Cronos Station when viewing the recordings, one of them containing info on Project Lazarus shows TIM discussing assembling a crew for Shepard, and how "We need sympathetic faces, we need Shepard invested" the obvious implication being Shepard will just walk on Cerberus due to a fundemental disagreement with them if they don't have close friends around them

But a question that arose in my mind was if you make Shepard be a human nationalist in ME1 who not only publicly backs the Terra Firma party, who have connections to Cerberus and push their interests in the Citadels political scene, but also make them distrusting and somewhat hostile towards the alien crew members of the Normandy, while also sacrificing the Council and replacing them with a Human one (Yes I know it was retconned and tbh it was a stupid idea) you've essentially made them the ideal Cerberus candidate

Not to mention Shepard can say to Miranda in ME2 that they wish Cerberus had extended an offer to join them earlier, and can defend Cerberus when crew members criticize them, it makes no sense lore wise why Cerberus would need to surround Shepard with sympathetic people to get them on board, when Shepard would already be sympathetic to Cerberus' core values, seems like at that point after Shepard woke up TIM would only need to say, "Hey so we know you're big on the whole Human nationalism thing, well guess what, that's what we're about, wanna join?" And Shepard would seemingly go, "Yeah let's get started" however despite all that in game the Illusive man will in reality go, "Miranda assumed you'd be resistant, she's not usually wrong" like bro what? Where tf did she get that idea considering all Shepard has done

Also it makes no sense for a Human nationalist Shepard to leave Cerberus but that's another thing entirely, development wise I know they wouldn't wanna record all the voice lines and make an entirely seperate campaign for ME3, especially considering how many people prefer Paragon and play that style their first playthrough, but is there any sensible in lore reason why? Or is it just something to be conveniently ignored?