I mean, he's right. What the hell is a farmer doing in Congress? But you're obviously not allowed to say that.
You're not allowed to say it because it's ridiculous. Are all farmers unsuited to service in Congress because they're farmers? That's flagrantly ridiculous. If not, what the hell does asking that question even mean?
Braley isn't wrong that Grassley's an odd choice for his Judiciary Committee position, but this is still a really stupid, awful sort of thing to say.
I think his point is that you should have some knowledge of law if you're in government, but it's certainly ridiculous to assume that a farmer has no knowledge of law or politics or that this somehow disqualifies them from holding office. Is it not completely obvious, at this point, that having a degree in anything doesn't mean s**t if your heart is in the wrong place and your judgment is clouded? Moreover, would a person like Lief vote for, say, Ted Cruz over a farmer based on difference in past occupations?