Why were they put to death?
Hatred for the faith, of course... but there was another reason people sometimes neglect to mention, or at times discount:
The ire of the Ugandan king was particularly inflamed against the Christians because they refused to accede to demands to participate in homosexual acts with him. Charles Lwanga, in particular, had protected the pages from King Mwanga's sexual advances.
Canonization Mass during Vatican II (source).
St. Charles Lwanga,
pray for us.