A4-sized posters that triggered the suspension of the organisation were placed on a noticeboard outside the library reading room last week.
The poster in question was from a grouping calling itself the Courage Community.
It invited people with "same sex attractions" to "develop an interior life of chastity ... to move beyond the confines of the homosexual label to a more complete identity in Christ".
The poster stated that this "purity matters initiative" was in conjunction with the NUIG Legion of Mary society.
NUI Galway says it is committed to protecting the liberty and equality of all students.
It reviewed the actions of the society in the context of the University's code of conduct and policies governing harassment.
This led to the immediate suspension of the Legion of Mary.
It is understood the society had only a handful of members.
In the region of 70 complaints were received.
The Societies Chairperson at the University, Patrick O'Flaherty, said he had been contacted by a number of students who were upset or felt threatened by the content of the poster.
Representatives of the Legion did not respond to an invitation to attend a meeting to consider the issue.
However, after the suspension was imposed, a committee member did write to the group apologising for any distress that had been caused.
She said the content on the document had been taken direcly from a website. It was not aimed at attacking any person or group of people and was not intended to hurt or offend.
The group had applied for status as a college society in September of this year and at one point had around 100 members.
As part of the application to become a fully-fledged society, its committee was asked to provide information as to its aims and objectives.
This did not happen. Concerns about the lack of clarification contributed to the decision to suspend the society.
In a statement, the University said it would not condone the production and dissemination of any material by students which discriminated against other students.
The Legion of Mary has apologised for any hurt caused.