Not really, just because they're selling order flow doesn't necessarily mean the customer gets a worse deal. Robinhood still has to follow reg nms, they have to fill you at the NBBO.
But is their NBBO worse than other firms (worse routing options)?
That's literally a contradiction. Look up what NBBO actually means.
It's actually more complicated, nbbo governs quotes but there are a few other things that affect your actual trade price such as exchange fees and price improvement.
For example, every exchange can have the same quote, but a different liquidity fee.
That's only true in the most technical of senses. Yes, there is a spread, but other brokerages take a spread AND additionally charge you another fee on top of that which is often an outrageous $5-10.
That outrageous $5-10 probably helps the average person make money in the long run by not overtrading.