I automatically assume the person who said it is a dick. Then I upbraid myself for misandry and assume they are an asshole instead.

tl;dr It is wrong to do that.

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Kicking out a child purely for being (or thinking they might be) LGBT is a fundamental violation of the role of a parent, which is to care for, feed, clothe, and house your child until such time as they are capable of doing so for themselves. You made the child, so you bear the responsibility of preparing it for life as an adult, no matter whether its sexual orientation is one you despise or if they don't happen to like your favourite sport.

I'd also suggest that such a parent would likely be in violation of the UN Convention on the Rights of the Child.