I've always thought of bullshit as being more about what you don't say than what you say. It's a lot easier to get away with bullshit when your bullshit consists of truths with a healthy dose of leaving important details that affect the implications of your statements out.
Such as something like, 'we've seen a dramatic increase in revenue' while leaving out the dramatic increase in expenditures and downplaying that profit hasn't really changed.
Or the kind of bullshit large companies use with the environment or social issues. Things like, our company uses 75% recycled products and cares about diversity, while leaving out that they destroy thousands of hectares of natural ecosystems, pollute land and water, oppress developing nations and murder their protesting citizens in the jungle while employing their children as slave labour. Meanwhile, they tell you how much they care about your rich, empty, disconnected technocrat concerns about the world and make you believe you're making a difference by buying their garbage and investing
in their company.
There's a kind of limbo zone where non-bullshitters internalize bullshitting as the normal pattern of communication and that's where the damage can really happen vis a vis genuine competence.
A manager might sit down with their team and say something like, "We are targeting 10% growth in our department revenue for next year." Someone raises the question on how that 10% growth will be achieved; what is going to be done differently next year than now.
There's a big difference between a person that can whip out their 10-page growth plan with concrete marketing and operational plans to explain how their proposed changes will lead to the desired growth versus one that simply states, "10% growth is a reasonable target for our division".
The latter is just parroting superficial, general information and (critically) thinks this is a sufficient or even desirable way to set goals (set a target and let the team hit it!). The former lets their quantitative conclusion "10% growth" follow from the actual work of building out a plan.
That's not the type of BS the author means, what you're referring to is called "falseness" by the author, eg. deliberate misleading statement. BS is more like sitting around with people telling stories and embellishing with some details that are irrelevant, or in the more useful case, discussing an idea that is incomplete without fear of the potential falsehoods impacting the creative process of exploring that idea. Say you're unsure of which car to buy, you could BS it in some story about your cousin buying that car (cousin actually bought a truck but that isn't the point of the story) and see how the people around you respond to it. Everyone who hates that car, while BS'ing with you is free to state it, but when you own that car already they have to hedge their opinions.
I wouldn't worry so much about what the "real" meaning of BS is. People clearly mean different things by it, and there's no reason to think there's one true answer. The interesting question is "Is the concept called 'bullshit' by Frankfurt a coherent idea that's useful for understanding the world?". If so, then in the present context we can call it "bullshit in the sense of Frankfurt", or "bullshit" for short, and get on with the non-semantical discussion.
Such as something like, 'we've seen a dramatic increase in revenue' while leaving out the dramatic increase in expenditures and downplaying that profit hasn't really changed.
Or the kind of bullshit large companies use with the environment or social issues. Things like, our company uses 75% recycled products and cares about diversity, while leaving out that they destroy thousands of hectares of natural ecosystems, pollute land and water, oppress developing nations and murder their protesting citizens in the jungle while employing their children as slave labour. Meanwhile, they tell you how much they care about your rich, empty, disconnected technocrat concerns about the world and make you believe you're making a difference by buying their garbage and investing in their company.