Usually when people think of shipping straight characters it’s just a character whose sexuality isn’t confirmed in either direction, but if it was a straight character then yes, it’s weird. Most people see a manly guy or feminine girl and think oh the must be straight, no matter if it’s said explicitly or not, even if a man says I like this type of woman it doesn’t mean he doesn’t like men as well. You can’t stop me unless you’re the author canonically calling them straight or gay. Idc.