Notice that these countries did not deploy until America said they were interested in Greenland. Russia and China have been eyeing Greenland as a strategic location for years and nothing from the EU. Answers once again that while the USA has been sending money, troops and aid to all these countries forever and a day, where would they be if America ever needed their help.
The USA is a NATO allie, the biggest and most important one.
Note there was no mention of benefiting any American security. Let these countries stroke off; do they really think sending a couple dozen troops there would really deter any country, the USA, Russia or China, from just walking right in there and take the whole place over?