Well, I am going to disagree a bit here.
TLDR: AMISOM is the African Union Somalia mission btw. Uganda provides 6k out of 20k soldiers.
Except for that, not much of an ally...
Uganda is generally seen as fairly supportive of Russia wrt Ukraine. It has generally abstained from UN votes on the subject.
Or...
South Africa, Senegal and Uganda have avoided censuring Moscow over the conflict, while Egypt, Zambia and Comoros voted against Russia last year in a U.N. General Assembly resolution condemning Moscow’s invasion.
Sonny Museveni's been quite pro-Putin, though muzzled a bit since: Uganda will send soldiers to Moscow to defend Putin if need be - President's son.
Re. Islamic State, is it asking much of an African government threatened by Islamic State to be against Islamic State? Does that, by itself, make for an ally?
Let's take a step back:
African states have their own reasons to sit on the fence wrt Ukraine war.
African states have their own reasons to fight against Islamic State, not least that Islamic State generally wants to eradicate all governments it is in contact with.
Most, but not all, African countries have a generally deplorable record when it comes to LGBTQ affairs.
The US gives aid to Uganda. This lot below is not military in nature:
The United States provides significant health and development assistance to Uganda, with a total assistance budget exceeding $950 million per year. The U.S. government plays a key role in improving health outcomes by strengthening Uganda’s capacity to sustainably address emerging health threats, tuberculosis (TB), malaria, maternal/child health, family planning, and HIV/AIDS (including by providing anti-retroviral treatment for more than 1.2 million Ugandans). Our assistance also focuses on boosting economic growth and agricultural productivity, including through improving educational outcomes; and supporting democratic governance through inclusive, accountable institutions. The U.S. mission is working with the government of Uganda to improve tax collection and oil revenue management, and to increase Uganda’s domestic funding for public services and the national response to HIV/AIDS.
Given the type of aid above, the suspension of it would not benefit Ugandans as a whole.
But a 2018 Reuters article did talk of an Uganda opposition request to suspend US military aid.
Washington is a major source of funding for Uganda’s military, supplying hardware, cash and training. It has given equipment, money and intelligence for the military’s hunt for Lord’s Resistance Army warlord Joseph Kony.
And Uganda apparently contributes to African security missions and gets separate aid packages for it.
Bilateral aid figures do not include much of the substantial
U.S. security assistance provided to support Uganda’s
participation in regional stability operations. Uganda has
been the largest recipient of U.S. support for AMISOM,
which has totaled roughly $2 billion in support to all troop
contributing countries. That total includes DOD “train and
equip” funding, of which Uganda has been among the
largest recipients in Africa. DOD has notified Congress of
over $280 million in equipment and training for Uganda
since FY2011; over $60 million in joint support to Uganda
and Burundi for AMISOM; and significant funding for the
2011-2017 counter-LRA effort. Uganda also receives
counterterrorism aid through State Department funds. It
received over $30 million in support via the African
Peacekeeping Rapid Response Partnership (APRRP).
Uganda’s North Korea ties have been a source of strain in
the U.S. relationship. Under pressure to comply with U.N.
sanctions, Uganda claims to have cut military ties in 2017,
but reports suggest some engagement may have continued.
So, "ally" seems to be stretching things a bit, more a marriage of some convenience. That said, LGBTQ tolerance seems extremely low in Africa in general so how much Uganda can be pushed on the subject remains questionable.
Cynically divorcing the status of ally from principles of good governance is not without risks, at the realpolitik level.
From Afghanistan to Vietnam and Pakistan, the US has had mixed results when backing regimes mired in corruption and inefficiency. In Latin and Central America, CIA backing for repressive anti-Communist governments has had a negative effect far outlasting Communism itself. However... nothing is simple: one could also cite Taiwan and South Korea, both ex-dictatorships as "success stories". As well as the disappointments of post-Arab Spring political evolution in the Middle East. Above my pay grade, but concerns about bankrolling a government like Museveni's are not ungrounded: at the very least there is the opportunity cost of making a better alternative less likely. Not that some European countries don't make the same mistakes either, mostly in Africa.
