2 John 1:11

because the person who gives him a greeting shares in his evil deeds. ¹ 

Anyone who welcomes him shares in his wicked work.

for the one who gives him a greeting participates in his evil deeds.

Anyone who encourages him becomes a partner in his evil work.

That would just give him a platform to perpetuate his evil ways, making you his partner.

For he who gives him words of love has a part in his evil works.

for to welcome is to participate in the evil deeds of such a person.

for he who greets him shares in his evil deeds.

because the person who gives him a greeting shares in his evil deeds. ¹ 

¹ sn Shares in his evil deeds. Giving a public greeting could be understood by an onlooker to suggest agreement with the (false) teaching of the opponents and is thus prohibited by John.