Why provide pronouns? 
Providing pronouns is important to ensure an inclusive environment where everyone's gender identity is respected. Using an individuals correct pronouns can help them feel welcome and included. 

Should only transgender/gender non conforming people provide their pronouns? 
No! Everyone has pronouns, and the use of pronouns by cis-gender people (i.e. people who identify with the gender they were assigned at birth) helps to normalise providing pronouns which can make trans and gender queer individuals to feel more accepted. 

What do I call someone when I'm unsure of their pronouns? 
If you are meeting someone and are unsure of their pronouns simply introduce yourself (e.g. my name is Sam my pronouns are he/him) and ask, what are your pronouns? Or simply use they/them pronouns or their name until there is an opportunity to ask! 

But, they/them is not grammatically correct is it? 
Actually, they/them pronouns are grammatically correct. We use them ALL the time! For example if someone left a jacket at your house and you're unsure who it belongs to. You would not say "He or she left a jacket at my house yesterday and I'm trying to find out who he or she is so I can return their jacket." You would simply say "they left a jacket at my house yesterday and I'm trying to find out who they are so I can return their jacket." 
Even if this was grammatically incorrect, I believe that affirming someone, making them feel welcome and included, by using their pronouns is more important than grammar. 

Why am I only recently learning about pronouns? Is it a new phenomenon or a fad? 
Actually, trans and gender diverse people have been around for centuries and its nothing new! These individuals have largely been erased from our histories due to a variety of factors including sexism and racism. Read more about the history of gender/sex and the influence of colonialism and sexism here: link link link
We also simply did not have the same terminology for these individuals we do now. 

I hope you learnt something new and that we can all work together for a future which is kinder, inclusive and welcoming to all.