"Consensus breaking" implies that consensus can never change.  It's fair to assume that no alternative clients have ever proposed a change with the ambition of becoming a minority chain that most users don't agree with.  But it's difficult to gauge support until users are actually running the code.  You can't put the cart before the horse and assume that every alternative client will be rejected by the majority just because it proposes a change to the current rules.

Otherwise, you play into the hands of BCH supporters who make claims that BTC development is centralised and that one dev team have total dominance over what the rules should be.  It's better if that decision is left to the users.  Which means allowing other clients to stand on equal ground and not sweeping them under the carpet as "altcoins", which smacks of social engineering.