Are other people doing it? -- So that is a reasonable test for ethical behavior? Wow. Other platforms similarly unethical behavior is NOT justification for lack of ethics. That might be a financial argument, but it is absolutely not a reasonable approach to ethics.
Legal vs. illegal is also not an appropriate basis for proper behavior. I think if we all used that standard for our personal interactions society would rapidly descend into chaos.
The behaviour of others is absolutely something that should be considered when deciding if something is acceptable behaviour.
Acceptable behaviour in a mosh pit is not acceptable behaviour in a grocery store check out line, because of how others are already acting and the pre established norms.
Ethics is not all that relative. Does SuperHuman allow tracking pixels for INCOMING emails from non-SH users by default? That would at least be non-hypocritical.
Legal vs. illegal is also not an appropriate basis for proper behavior. I think if we all used that standard for our personal interactions society would rapidly descend into chaos.