Feelings come from somewhere. When I try to engage people, I try to address root causes of feelings. I don't try to massage their feelings or something like that.
Most people either try to somehow stop the outpouring of negative feelings or respond by countering it with an outpouring of positives because their entire focus is the feelings. This tends to go bad places for everyone involved and one danger is that if everyone is nice to you when you are openly whining about being suicidal, that may actively "reward" you for being suicidal.
People who are suicidal are often people who are being generally treated like shit on a routine basis by a lot of the people around them. So being nice to them only when they are openly suicidal actively encourages suicidal ideation. Most people are too clueless to make an effort to find opportunities to engage them positively that don't promote suicidal feelings.