All 3 examples you provided are for people trading on material nonpublic information. In other words, some guy working at an asset manger knew they were going to execute trades on behalf of a client, and then made his own trade ahead of that. That's textbook front running, no denying it, but that's not anywhere close to what's happening with "ETF rebalancing" or PFOF. It's perfectly legal, for instance to speculate on whether TSLA or whatever is going to make it into the S&P 500 and "front run" that. It's also not clear why such trades would be immoral or unfair.

>https://www.sec.gov/newsroom/press-releases/2021-118

>Wygovsky repeatedly traded in his family members’ accounts held at brokerage firms in the United States ahead of large trades that were executed on the same days in the accounts of his employer’s advisory clients.

>https://www.sec.gov/newsroom/press-releases/2021-186

>Polevikov had access to real-time, non-public information about the size and timing of his employers' securities orders and trades, and used that information to secretly trade on, and ahead of, his employers' trades.

>https://www.sec.gov/newsroom/press-releases/2022-228

>Billimek would inform Williams of the asset management firm’s market-moving trades prior to their execution