All marked points are legitimate signals. Claims of illegitimacy could be made if all signals over time result in a successful trade. Any active trader understands that ANY signal no matter how clean or strong can fail and there is no way of knowing before hand which trade (s) will result in a profit or a loss. The best any of can do is have an edge with a trade plan to preserve it and the discipline to trade it according to the rules of the plan.
Sideways markets can be traded but they require different methodologies and only then with adequate range. Such conditions are not recommended for a new or developing trader and are not necessary to trade for anyone. Patience for any trader is vital and markets will breakout and trend at some point.
Digging the visualizevalue timeline lately, this graphic illustrates the concept you allude to;
