When you say "all", do you mean Wim Hof's methods or in general breathing techniques? Do you have links to studies which have conclusively proved that breathing techniques are no better than normal breathing?
What most people who are "anti-breath work" seem to not take into account is ig someone's baseline breathing is good to begin with or not - and simply drawing their attention back to their breath could bring them back to within a normal range; maybe someone's chest is tight and they have abnormal breathing, maybe someone's nose is congested most of time so they mostly mouth breath, etc - but aren't aware their breathing is so constricted/limited until they start to challenge the status quo breathing they've adopted over decades - to finally start feeling what normal baseline of getting adequate/proper oxygen exchange feels like.