How did facebook DDoS do it?

About a day ago, my router was being DDoS by some people and one of the IP addresses was that of Facebook. Can someone explain this?

[DoS Attack: ACK Scan]    after the source: 31.13.65.50, port 443, Saturday 23 February 2019 16:49:04
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 5222, Saturday 23 February 2019 16:48:41
[DoS Attack: ACK Scan] Source: 31.13.65.50, port 443, Saturday 23 February 2019 16:47:01
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 5222, Saturday 23 February 2019 16:46:38
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 443, Saturday 23 February 2019 16:44:58
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 5222, Saturday 23 February 2019 16:44:35
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 443, Saturday 23 February 2019 16:42:56
[DoS Attack: ACK Scan] from source: 31.13.65.50, port 5222, Saturday, 23 February 2019 16:40:29
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 5222, Saturday 23 February 2019 16:36:24
[DoS Attack: ACK Scan] from source: 179.60.192.3, port 443, Saturday 23 February 2019 16:27:07
[DoS Attack: ACK Scan] from source: 31.13.65.50, port 5222, Saturday 23 February 2019 16:24:53
[admin login] from source 192.168.1.18, Saturday, February 23, 2019 at 4:24:12 pm
[DHCP IP: 192.168.1.18] at the MAC address, Saturday 23 February 2019 16:23:46
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 5222, Saturday 23 February 2019 16:18:45
[DoS Attack: ACK Scan] after the source: 31.13.65.50, port 5222, Saturday 23 February 2019 16:16:42
[DHCP IP: 192.168.1.18] at the MAC address, Saturday 23 February 2019 16:12:06
[DHCP IP: 192.168.1.2] at the MAC address, Saturday 23 February 2019 16:00:28
[DoS Attack: RST Scan] from source: 188.122.82.214, port 80, saturday 23 february 2019 at 15:57:23
[DoS Attack: RST Scan] from source: 72.167.239.239, port 80, Saturday 23 February 2019 15:54:11
[DHCP IP: 192.168.1.4] at the MAC address: ec, Saturday 23 February 2019 at 15:53:55
[DHCP IP: 192.168.1.8] at the MAC address, Saturday 23 February 2019 at 15:48:39
[DHCP IP: 192.168.1.35] to the MAC address 20: df: b9: announcement: 1c: 38, saturday, 23 february 2019 15:40:16
[DoS Attack: TCP/UDP Chargen] from source: 210.129.88.228, port 17564, Saturday, February 23, 2019 15:33:45