Both narratives are fake.
18: There was an average of 0.5 Illegal Contact penalties per team league wide.
17: There was an average of 1 Illegal Contact penalties per team league wide.
This is per team, not per team per game. You're comparing 4 weeks to a whole season. That site doesn't count offsetting or declined penalties, which I'm guessing is the difference between the 16 and 24 count for this season.
Illegal contact penalties in the NFL have tripled this season compared to the same period last year, a largely unnoticed factor among those fueling a record-setting start for offenses.
This is because the number of illegal contact penalties at the beginning of the 2017 season was unusually low, not because this year is unusually high. The number in 2018 is lower than in 2016 and way lower than in 2014 or 2015.