1) Google and Facebook represent only a very small and very elite slice of the developer market. This bizarre focus on what happens at the top 0.5% of the market has a distorting effect. The rest of the market is ignored in this analysis.
2) No mention of dollars spent on training vs. dollar return in labor savings. If Google spends $1 billion on education over 20 years which provides a labor savings of $500 million then they are losing out. The article speculates that there will be a net profit on labor savings but provides no data or evidence to back it up.
3) Developer salaries may actually be inflated. In which case it's only natural that many people would try to get into the market, either by participating in MOOCs, getting a computer science degree, being self-taught, etc. The article assumes it's exploitative to help people break into this market, because the MOOC companies operate at a profit and it might reduce developer salaries overall. But people are going to find their way into the market on way or another. Even if we got rid of all the MOOCs and all the tech education initiatives talented people are going to flock to these industries.
4) Article ignores positive effects. Lower developer costs mean smaller companies or less-than-rich individuals can hire talented developers to build a new service or start a new company. Developers might be paid 10%-20% less, but we would also end up with more developers total. The net benefit to the labor market as a whole would be positive.