I think it's always the weight of many instances, it's not the particular fish finger mother.
I would even say that most people don't think there needs to be some exact representation of the public's demographics, people understand that advertisers want to represent differernt kinds of customers. Or some items may be marketed to specific groups because those are the customers.
It's when it seems very far out of balance overall that people think something is being pushed, whether they believe that to be some kind of comment about white people being uncool, or virtue signalling, or something else. When it's blatant enough that you start to notice it's really out of step with the reality around you, you have to wonder why.
I'd add to that, most people don't respond well to moral lectures from corporations.
I have wondered at times, given how out of skewed representation is with actors, not just in advertising but in the theater, if it is harder for young European actors to get started compared to non-white actors. From anecdotes I've heard from the few people I know who work in that area I suspect that it is a disadvantage.