Here the Master speaks of the gospel as a sort of drag-net that sweeps along and pulls everything toward it. The gospel goes out and is heard all over the world and from this net will be taken “fish” of every sort (Revelation 7:9-10). Yet only some fish will be staying for supper (Revelation 19:6-9). The net captures many kinds of fish, but at the end of the day, the fisherman judiciously separates the bad from the good, and keeps the edible fish but throws away those that are no good to him.
The gospel is for all people, and all people groups, and Jesus is the only Savior, the only way we can have eternal life (John 14:6 / Acts 4:12 / 1 Timothy 2:5). The call of salvation wasn’t localized to a particular place or people and is not limited to a particular time period (Romans 10:18 / Colossians 1:6, 23 / 1 Timothy 4:10 / Titus 2:11 / 1 John 2:2). From every nation God will get Himself a people, but not all people will come to Him in faith and be saved, of this we are sure (Matthew 7:21).
There are people who hear the gospel but deny it (2 Thessalonians 1:8), devalue it (Romans 10:16), distort it (Galatians 1:6-9), dismiss it (Hebrews 6:4-8), or who are otherwise deceived about it (2 Corinthians 11:4) and dead to it (2 Corinthians 4:3-4). This includes many people in the visible church. They appear to be “good fish”, and they are visibly in the net, but nevertheless they are not the children of God.
The call of the gospel is like a net, it is indeed universal, but only those who will receive it are saved (John 1:12, 17:3 / Romans 10:9-13). The question is whether or not you are following along in faithful trust or just getting taken along for the ride.