I saw that. When you decide whether to scalp vs bet, you need to know the long term ROI of each position.
Its easy to calculate with the scalp, not so easy with the straight side which is why people just blindly scalp.
Unless you get a really fat scalp, the straight bet (ie, keep the weak line) will have a higher ROI but is riskier and people aren't comfortable betting $5k on a game but will easily lay $5k on both sides of a +110 line since their is no risk involved other than the book not paying.