So are you suggesting that Welsh speakers shouldn't be allowed to speak Welsh? Surely that is a breach of a fundamental human right? Censorship, whatever you want to call it.
You cannot impose a situation whereby Welsh speakers are not allowed to speak Welsh, no more than you can impose a situation whereby non Welsh speakers have to understand Welsh. A Welsh speaker would be perfectly entitled to talk to me in Welsh if they desire. The fact I won't understand half of it might just change the situation if that person wants me to understand them.