@z in academia, LGBT(Q) refers to any alliance of lesbian, gay, bi, trans (and queer) organizations or movements, each of which may only identify with a few of those labels. it is a heterogeneous term which serves as an umbrella for antihomophobic activism and support in general.

queer, on the other hand, is a more specific set of movements concerned primarily with dismantling or contesting normative ideas of gender and sexuality. it's generally not a label one applies to people or organizations who haven't taken the label on themselves.

on an individual level, generally the organizations which describe themselves as queer are more progressive and accommodating than those which describe themselves as LGBT, and are more political at heart. but in aggregate, LGBT draws the widest net over organizations or movements.

re: spaces, using the term “LGBT” similarly suggests “we are looking to accommodate people who are gay but aren’t committed to the queer movement”, which can be good for some things (support groups), and bad for others (political activism)