How does intent negate a sacrament?

[JJMG2001]

I understand that one must intend to perform a sacrament in order to. But something isn't clicking for me. I know that the Anglicans don't have valid holy orders because their understanding of priesthood a while ago made it impossible to have the necessary intent to ordain. But I know that many protestant sects don't view baptism as a sacrament. They merely intend to symbolize someone’s entrance into the search and symbolize the forgiveness of sins. But their sacraments are still valid. So why when the Anglicans don't understand the sacrificial nature of the mass is their ordination invalid but when other protestants don't understand that Baptism isn't symbolic or that it even has anything to do with forgiveness or initiation are theirs still valid?

[cappie]

Not all church's baptisms or christenings are recognised by the Catholic Church. Usually there has to be an agreement on the meaning of baptism before a baptism by another church is recognised as valid. E.g in Australia the following baptisms are regarded as valid...Anglican(Episcopal) Uniting, Methodist, Congregational, Presbyterian, Lutheran, Orthodox, all others may be baptised conditionally if there is doubt about the OFFICAL teaching of the denomination. I'm not too sure about the US. In the case of the Anglican Church and orders regarding ordination and Eucharist the Intention of the reformers was to do the opposite of the Catholic Church and so valid orders died out. In regards to baptism there is agreement on a comon faith re baptism and so as you do not need a validly ordained minister then the baptism is valid.

INTENTION: The Minister must have the proper intention. That is, he must intend to do what the Church intends, or what Christ intends (which is in fact the same thing). Intention is usually seen as having both an external and internal aspect. The external intention is provided to the minister by the rite he uses and it is assumed that he intends what the rite intends. His internal intention is another matter and can never be known with certainty unless he exposes it or makes it known. The minister can, by withholding his internal intention, or having an internal intention that contradicts that of the rite, obviate or prevent the effect of a Sacrament. The Church, recognizing that it can never know the internal intention of the minister, assumes it is the same as his external intention, (the intention which the traditional rite provides by its very wording) unless he himself informs the Church otherwise.