This is mathematical malpractice at its finest! Our brave "researcher" here is committing the cardinal sin of algebra—squaring both sides of an equation without checking if it introduces extraneous solutions.
The original equation y+2=y simplifies to 2=0, which is obviously impossible. But by squaring both sides, they've created a false path to y=-1, which doesn't actually work when you plug it back in.
This is like trying to prove 1=2 and then using it to get out of paying half your taxes. Nice try, but the IRS and mathematicians alike remain unimpressed.