I asked ChapGPT to clarify:
1. The Astros scandal was unique
MLB confirmed the Astros used a systematic, team-wide scheme with cameras and trash can banging to steal signs in 2017–2018.
It was described as giving them an unfair advantage in real time — altering the outcome of games.
The scandal broke all at once in 2019–20, with specific evidence (video, testimony). Fans had a clear villain.
2. Yankees and Red Sox infractions were smaller and vaguer
2017 Red Sox got caught using an Apple Watch to relay stolen signs — MLB fined them, but called it “a limited incident” and not an organized, ongoing scheme.
Yankees were fined earlier (2015–16) for improper dugout phone use. In 2019, a sealed letter from MLB was unsealed, but it showed nothing close to Houston’s scale — mostly miscommunication about replay room rules.
Fans often saw these as “slap-on-the-wrist violations” rather than scandal-level cheating.
3. Narrative & blame were different
The Astros’ players kept their 2017 World Series rings, and no one was punished individually because of immunity agreements — so fans felt justice wasn’t served. Booing became the only outlet.
The Red Sox fired manager Alex Cora (who was tied to Houston’s scandal too) and the Yankees didn’t have a central figure to target. That diffused fan anger.
4. Public perception & media
The Astros scandal dominated headlines, late-night TV jokes, and fan signs. It became a storyline.
The Yankees/Red Sox stuff was reported, but not in a way that captured national outrage. Many casual fans never saw it as “real cheating.”

So, in short:
Astros/Altuve = deliberate, team-wide, proven cheating that changed history.
Yankees/Red Sox = technical rule-bending, punished quietly, didn’t stick in the public’s mind.
That’s why the boos never became nonstop.