I have seen Church teachings about vocations and about single life. Some put the two of them together others do not.
Here are some that say single life is not a vocation:
osv.com/tabid/7621/itemid/8196/Is-the-unconsecrated-single-life-a-vocation.aspx
ericsammons.com/blog/2010/01/13/why-the-single-life-is-not-a-vocation/
If you read
Vita Consecrata (The Consecrated Life) you will see that those who consecrate themselves privately, including outside of private vows, to a Gospel Way of life, are included in this document and under the heading of “Thanksgiving for the Consecrated Life”. Hence any website stating to the contrary is doing so
against what The Church teaches and The Catholic Catechism states.
Very sadly, the Church’s teaching on the lay celibate chaste vocation (“single life” in the colloquial, but this is not strictly Catholic Church terminology. “Single life” is a secular colloquial term) is scattered in various places in the Catholic Catechism and also in Church Documents. There is not, to date that is, a specific document on the Celibate Chaste Vocation to The Laity or similar title. Perhaps it will be written given time. With all the contention around as to whether it is a distinct state in life and an actual vocation, we need such a Document to specifically point out what The Church teaches and the general terms and conditions under which such a way of life should be lived - all located in the one Document.
Many priests and religious, spiritual directors, nowadays are quite familiar with single life (celibate chastity in the lay state of life) as a potential call and vocation in life and what it entails and does not entail - sadly, very sadly, not all priests and religious nor spiritual directors are aware - or being aware choose to dismiss it and contrary to what The Church teaches.
Our baptism in The Church is our first, or initial, call and vocation to holiness and to embrace Jesus and His Gospel in His Church. It places the baby, child or person, whoever is baptised, in the lay state which is a distinct state of life in The Church i.e. distinct from all others with its own duties, responsibilities and accountabilities - and whether one is married or single.
We certainly do have an apostolate of the Laity Document:
vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_decree_19651118_apostolicam-actuositatem_en.html
Secular institutes for example existed before The Church included them in the consecrated state of life.
Those who choose to embrace the single or lay celibate state as their
vocation in life are choosing a valid and quite distinct state of life in The Church as their vocation. One could not live out this vocation unless the Grace is granted to do so. Celibacy is not for all, not all receive this call and vocation, nor are all called to marriage as their primary attraction in life.
vatican.va/roman_curia/congregations/ccscrlife/documents/hf_jp-ii_exh_25031996_vita-consecrata_en.html** "Thanksgiving for the Consecrated Life **
… We are all aware of the treasure which the gift of the consecrated life in the variety of its charisms and institutions represents for the ecclesial community.
Together let us thank God for the Religious Orders and Institutes devoted to contemplation or the works of the apostolate, for Societies of Apostolic Life, for Secular Institutes and for other groups of consecrated persons, as well as for all those individuals who, in their inmost** hearts, dedicate themselves to God by a special consecration.