@rinrang Gonna be frank with you, if you only want to read yaoi and yuri manga, there are other sites or forums that cater only to those genres. Even manga listing side or other aggregator sites don't have hetero/straight tag, the only site that have hetero sex tag is myreadingmanga as far as I know, which only posts yaoi. If you have problem with specific types of tas/genres (eg sexual violence/rape, or loli, incest etc), you can choose to black list those tags in your personal settings and you won't see them anymore.
https://mangadex.org/settings
Scroll down to Exclude tags and there you go.