I have no problem with people feeling pride about their immutable characteristics. Scottish and proud? Excellent, go put on a kilt and throw one of those giant poles; looks fun! I have a problem when "pride" is used to organize people against a vulnerable minority. So sure, enjoy your super straight free beer with a bar full of other totally straight cis men and talk about... Idk sports or something. However, given the current political climate it seems to me like this is likely a way to gather people resentful of LGBT pride's efforts to claim equal rights. So it isn't a gathering of proud straight men, it is likely a gathering of bitter hateful men.
LGBT pride exists to fight for equal rights and representation that cis-hetero people enjoy by default; it isn't meant to gain an upper hand or displace cis-hetero people. Far-right extremists like to paint the movement's goals as a way to erase white straight cis culture, but this is just reactionary propaganda to mobilize people against this minority group.
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