Yeah. He says it well.
And I will add to it. Where is it stated that the things that are done require that there be an opportunity to preach the gospel (meaning speak about Christ) to be valid? Of you decide to serve meals at a homeless shelter and they do not want anyone making religious comments of any kind, should you refuse to serve?
Surely you should still serve. The act of refusing is to be exactly opposite of the one who was and still is our example — Christ.
And I will make an unpopular point on the quoting of Mark 16:15. Just like in Matthew, who was he talking to? To the eleven. Not even the 70, or the 500. Or to a huge assembly such as in the sermon on the mount.
But he was clear that the first commandment was to love God, and the second was like it — love your neighbor as yourself. And in one of the accounts he defined neighbor as unthinkably broad.
Can this be excluded from the mission of the church just because he did not include the word "church" when he commanded it?
So do you love yourself enough to want a hospital for your medical care? Then where is the restriction on how we love others, including giving to the building of hospitals that can care for them.
It is in the overt refusal to be part of that, or at least some such activities, that you prove your lack of love for your neighbor. I would agree that we cannot all do everything. And everyone does not have to give to this or that. Or help with every charity that we hear of. And not everyone is gifted enough financially to give to a lot of such things. So being selective is one thing. But refusing because you think it is not you job is to prove a lack of understanding of the scripture. And to prove a lack of love for neighbor.