Unused EB-5 visa numbers spill over to EB-1, and EB-1 to EB-2, and EB-2 to EB-3. This bill would eliminate the EB-5 -> EB-1 spillover, which has the effect of reducing the number of EB-2 and EB-3 green cards available per year.
regardless, it's also not the case that all other backlogged visas are of higher priority than new visas. if there is a zero-sum game to be played, priorities could well be reviewed for all types of visas.
your argument for not approving this legislation seems to revolved solely around the backlog issue. there are other better ways to solve that problem than by simply stonewalling all other visa legislation.