It's legal if they don't get caught.

Many of us have sent numerous complaints to Finra and the SEC about price manipulation. I have sent multiple and actually spoke with Finra. They do not care about penny stocks.

Below is an L2 snapped about 10:10 EST. The bears are trying to prevent a close above the 20 DMA because that combined with the MACD cross from a week ago is the green light for many technical and momentum traders.