The point of these lines is clear. In the old days, craftsmen did not cut corners. They worked carefully, and they took care with every aspect of their work. Every part of the product was considered, and each was designed and made to be exactly as it should be. These craftsmen did not relax their thoughtful self-discipline even with respect to features of their work which would ordinarily not be visible. Although no one would notice if those features were not quite right, the craftsmen would be bothered by their consciences. So nothing was swept under the rug. Or, one might perhaps also say, there was no bullshit.