In Spanish, we have the standards set by the Royal Academy of teh Spanish Language, basically, to agre on how to write stuff or proper grammar. Because when you have a billion people mangling the same language, with regional accents and lexicon and usage, you need some standard to follow for politeness, so you can be understood.
I always compare teh Mainlanders to the Spanish criollos. I mean, you have this mayority, in our case, lighter skin. Mot people descend from one Indigenous female and one Spanish male -don't wanna know the details about that, with African and Asian thrown in for good measure - like yours truly. There was a need to justify the conquest based on religion -in Taiwan's case, based on te fight against Communism-, cultural domination -well, massacre, and eventually, teh dominated identify with the dominator - like the civil servants/military who deny or denigrate their Southern roots because they had to pledge alliance to the Party/State first many years ago. That the taiwanese are starting to pull away from this mentality, regaining their history, revaluing their autonomy and cultural authenticity, is loable.
But denying use of hanyu pinyin is shooting themselves in teh foot, just as rejecting use of English. What is necessary is to take away the cultural domination teeth off these tigers and subjugate them to the cause, use them for what they are: tools. Don't make them into cargo cults or supernatural forces that will take you over. Use them as you use a computer. I always told that to my students. Make them work for you. You do not have to become gringo and choose hamburgers over houguo because you need to learn English. Same for hanyu.