No, you miss the point. It may be impractical but it's not "irresponsible" to go into debt to be a social worker, unless you think all that matters is your own income. It is an argument for the cost of education to be paid by the government, at least when the real return on investment for society is more than the amount borrowed.
If you said you borrowed $100K to become, say, a stock broker, I would agree with you, as that requires little education and is of questionable value to society.
Maybe the government should subsidize majors that have the greatest potential immediate value to society as a whole relative to expected individual income. Of course, that begs some big questions, but at least it's less expensive than subsidizing everybody and would incentivize important low income professions. Places to start include social workers, teachers, nurses. No doubt those who think that the market always determines the correct value of everything will not agree.
PS: This is also an argument for subsidized trade schools. Who offers more to society, a good plumber or your average business major?