In general, yes, but the article needs context. A quick search of the 15th Amendment vote, which granted equal voting rights regardless of race (February 3, 1870) shows the following as just one example:

House vote was 144-44 with no Democrats voting in favor, 39 Democrats voting "no" and eight Democrats not voting. Senate vote was 39-13 with all "yea" votes being Republicans. Not sure how they got the percentages they used but the immediate post-war measures passed in Congress were highly partisan votes.

It is true that the Democrat South in the post-war era was not friendly to many civil rights initiatives -- and it's not politics to say that, it's fact. All the way to the Civil Rights Act of 1964, which was passed thanks more to Republican support than Democrat, this was the case.

That said, gatewaypundit is a known conservative source for information and reading the article should take that into consideration.

EDIT: And now that I think about it, it's useful to understand why the Republican Party was formed. Initially it had two main planks: anti-polygamy (Utah was a very big issue at that time) and anti-slavery. Such was the anti-slavery sentiment among elected Republicans of that day that Senator Charles Sumner of Massachusetts did not vote on the 15th Amendment despite being arguably the most anti-slavery member of Congress, because it didn't go far enough to suit his wishes.

Sorry that this is so late - but yeah this is a pretty one sided article that doesn't really put a lot of things into context.

At first, the article is largely correct The Republican Party was very much the party of Civil Rights until about the late 1950s and 60s. The article then talks up every pro-civil rights stand by Republicans while downplaying anything that doesn't support their political position.

Major civil rights legislation was passed (1964 civil rights act, voting rights act) because of an alliance of liberal non-southern democrats and northeastern/mid-western republicans. Lyndon Johnson championed these laws - his influence and lobbying was instrumental for their passage. (see LBJ's We Shall Overcome speech)

It's notable to mention that Barry Goldwater who ran against LBJ in 1964 was against the Civil Rights Act as were notable figures such as Ronald Reagan and George H.W. Bush (who was a congressman at the time).

The backlash against civil rights gave an opening to the Republicans to win white votes in the south - which is how the Republicans gained a foothold in the south and prominent democrats like Strom Thurman and Jesse Helms switched parties to the GOP.

Source: Robert Caro, Years of Lyndon Johnson