Unbiblical? The Bible doesn't call people to preach. God does. And sexism is a sin and against Pauls decree in Galatians concerning the oneness in Christ.
No, it isn't unbiblical. Galatians 3 shoots that argument right out of the water. Anyone that would like to insist on that line of falsity would be calling Paul either a liar when he wrote to the churches in Galatia, or deluded.
Why were women to be quiet in the churches in Corinth? Why would Paul write a totally different letter to the churches in Galatia about women? Because he wasn't talking about the woman's capacity to be called by God to preach.
In 1 Corinthians 14 and verses 27-35, Paul tells a number of people how to behave in church. His letters were a matter of restoring order and maintaining decorum during the service. Not saying women cannot preach. If it were true that women are to keep quiet in church there would not be a woman in the choir. Nor in any office that serves in the church. Because she would then be not quiet in her service to and within the church.
The Bible does call people to preach:
Mark 16:15 And he said unto them, Go ye into all the world, and preach the gospel to every creature.
1Cor 1:21 For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe.
2Tim 4:2 Preach the word; be instant in season, out of season; reprove, rebuke, exhort with all longsuffering and doctrine.
These are but a few verses and to say that these verses that are written in the Bible does not tell you to preach but God does is blasphemy as the Bible is the word of God.
2Tim 3:16 All scripture
is given by inspiration of God, and
is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
2Tim 3:17 That the man of God may be perfect, throughly furnished unto all good works.
Rom 15:4 For whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the scriptures might have hope.
This then surely tells us that what is God breathed is from God because it is not man breathed and for that I thank God.
So the Bible does call people to preach because it is impossible to separate God from His word and that is the truth!