Complex sentence: Säde is very loud-mouthed and rude to B. Virtanen and Reino Murikka and disinterested in her job, but Virtanen and Murikka don't dare complain because their superior happens to be her uncle.
Split into simpler sentences: Säde is very loud-mouthed and rude to B. Virtanen and Reino Murikka and disinterested in her job. However, Virtanen and Murikka do not dare complain because their superior happens to be her uncle.