[Tailgunner Joe]

If the Founders wanted the establishment clause to forbid endorsements as well as establishments then wouldn’t they have wrote it that way?

[BocoLoco]

"If the Founders wanted the establishment clause to forbid endorsements as well as establishments then wouldn’t they have wrote it that way?"

They did. It's right there. No establishment of religion by by the government. No support of any religion by the government. Congress is not to meddle into religion, period nor provide preferential treatment. Until several key SCOTUS rulings in the early part of the 20th century, states had not been affected by the 1st Amendment.

But here's some extra information directly from the First Congressional notes from 1789 just so that it's even more clear to everyone what the intent was...

September 3, 1789:

On motion to amend article third, and to strike out these words: 'religion, or prohibiting the free exercise thereof,' and insert 'one religious sect or society in preference to others:'

On motion to amend the third article, to read thus: 'Congress shall make no law establishing any particular denomination of religion in preference to another, or prohibiting the free exercise thereof, nor shall the rights of conscience be infringed:'

Both were passed in the negative (rejected). It continues...

September 9, 1789

On motion to amend article the third, to read as follows: "Congress shall make no law establishing articles of faith or a mode of worship, or prohibiting the free exercise of religion, or abridging the freedom of speech, or the press, or the right of the people peaceably to assemble, and petition to the government for the redress of grievances:

This was passed in the affirmative (later to be amended).

It's clear from the back and forth motions in the Senate that the intent was to keep religion out of the Federal Government, especially Congress. Any endorsements would be a violation of Amendment I as it would indicate preferential treatment toward one religion over another.