And the priests being unmarried (Due to church obligatory policy), should not be fathers at all. It is a complcated un-natural vicious circle of terminology which has been spun by the church, around simple real life matters/ relations.
It’s not at all unnatural. If you would read your Bible, you will see that St. Paul often called his converts “sons.”
I quote from the King James Bible – I trust it’s Protestant enough.
“I write not these things to shame you, but as my beloved sons I warn you.” (I Cor 4:14)
“For this cause have I sent unto you Timotheus, who is my beloved son…” (I Cor 4:17)
"19 But I trust in the Lord Jesus to send Timotheus shortly unto you, that I also may be of good comfort, when I know your state. 20 For I have no man likeminded, who will naturally care for your state. 21 For all seek their own, not the things which are Jesus Christ’s. 22 But ye know the proof of him, that, as a son with the father, he hath served with me in the gospel. (Phil. 2)
“Unto Timothy, my own son in the faith…” (I Tim. 1:2)
“This charge I commit unto thee, son Timothy…” (I Tim. 1:18)
“To Timothy, my dearly beloved son…” (2 Tim. 1:2)
“Thou therefore, my son, be strong in the grace that is in Christ Jesus.” (2 Tim 2:1)
“To Titus, mine own son after the common faith…” (Titus 1:4)
“I beseech thee for my son Onesimus, whom I have begotten in my bonds…” (Philemon 1:10)
And St. Peter also used the same term for Marcus:
“The church that is at Babylon, elected together with you, saluteth you; and so doth Marcus my son.” (I Peter 5:13)
St. Paul used “father” applied to himself when writing to the church in Corinth:
“For though ye have ten thousand instructers in Christ, yet have ye not many fathers: for in Christ Jesus I have begotten you through the gospel.” (I Cor 4:15)
And to the church in Thessalonia he wrote:
“As ye know how we exhorted and comforted and charged every one of you, as a father doth his children…” (I Thess 2:11)
St. Paul wrote to the Corinthians:
“Now for a recompence in the same, (I speak as unto my children,) be ye also enlarged.” (I Cor 6:13)
And…
“Behold, the third time I am ready to come to you; and I will not be burdensome to you: for I seek not yours but you: for the children ought not to lay up for the parents, but the parents for the children.” (2 Cor 12:14)
And in Galatiians:
“My little children, of whom I travail in birth again until Christ be formed in you,” (Gal 4:19)
And St. John wrote:
“My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous:” (I John 2:1)
“I write unto you, little children, because your sins are forgiven you for his name’s sake.” (I John 2:12)
“I have no greater joy than to hear that my children walk in truth.” (3 John 3:4)
Apparently the Apostles (who learned at the feet of Jesus) were not afraid of a spiritual father/son relationship with their converts. By your reasoning, shouldn’t they have called them their brothers and sisters instead of children and sons? Perhaps the one verse in the Gospel is not as clear cut as those who wish to attack the Catholic think.
May God be with you